if

英[ɪf]美[ɪf]

conj.如果，倘若，即使，〈口〉是否，假设；

n.条件，设想；

复数：ifs;

英语六级真题

Will parents be damaging children if they have one fewer organized activity? No, I really doubt it.

White storks feed on locusts ( ' , 蝗虫) and other insects that can become pests if their numbers get out of hand.

Unless renewables become cheap enough that substantial carbon deposits are left underground for a very long time, if not forever, the planet will likely be exposed to potentially catastrophic climate risks.

The challenge is if certain types of people are doing something, it's difficult for other people to break into it, said Po-Shen Loh, the head coach of last year's winning U.S.Math Olympiad team.

Progress in the development of renewables could be fragile, however, if fossil fuel prices remain low for long.

Participation grows through friends and networks and if you realize that's how they're growing, you can start to take action and bring in other students, he said.

Moreover, nonparticipation by nations, if sufficiently widespread, can undermine the political will of participating countries to act.

If you look at a lot of low-income communities in the United States, there are programs that are serving them, but they're primarily centered around ‘Let's get these kids' grades up,' and not around ‘Let's get these kids access to the same kinds of opportunities as more-affluent kids,' said Daniel Zaharopol, the founder and executive director of the program.

If not corrected by the appropriate carbon price, low fossil fuel prices are not accurately signaling to markets the true social profitability of clean energy.

If Paris was cast aside, the tradition of beauty was also to some degree slighted.

Greenhouse gas emissions, if not properly dealt with, will pose endless risks for mankind.

If you think this does not apply to you, then here is a simple test to show you are wrong.

Whether this is right, and if so where and when the ecological axe will fall, is hard to determine with any precision—which is why governments and financial institutions are only beginning to bring such risks into their economic calculations.

They need to know if reform will help solve the problem.

That would be true only if you believed that patients should have an unrestrained right to treatments proven to be inferior.

That is far less likely to happen if Congress also adopts strong pay-go rules requiring that any increase in payments to providers be offset by new taxes or budget cuts.

Saying that there're no easy answers sounds wise, but it's actually foolish: our unemployment crisis could be cured very quickly if we had the intellectual clarity and political will to act.

Our society needs the full participation of its younger citizens if it is to continue to thrive.

If this is not happening today, we should ask why.

If such an indicator exists, it is well hidden.

If private plans demanded similar productivity savings from providers, and refused to let providers shift additional costs to them, the savings could be much larger.

If our economies are to flourish, if global poverty is to be eliminated and if the well-being of the world's people enhanced—not just in this generation but in succeeding generations—we must make sure we take care of the natural environment and resources on which our economic activity depends.

I'd be sympathetic if the union focused solely on higher compensation.

Get a teacher from the top 20%, and it's as if a child has gone to school for an extra month or two.

Get a bottom 1% teacher, and the effect is the same as if a child misses 40% of the school year.

Now Fred, you went to university in Canada?( ' , 9 ) A recent International Labour Organization report says the deterioration of real wages around the world calls into question the true extent of an economic recovery, especially if government rescue packages are phased out too early.

Is there really a magic memory pill or a herbal recall remedy? I have been frequently asked if these memory supplements work.

What happens to the centralized electric grid, which took decades and billions of dollars to build, as more and more people become prosumers, who produce and consume their own energy on-site?No one knows which – if any – battery technology will ultimately dominate, but one thing remains clear: The future of energy is in how we store it.

There must urgently be a meaningful mobilisation of the policies outlined in the agreement if we are to achieve national emissions reductions while helping the most vulnerable countries adapt to climate change.

Studying at university will only become less attractive if employers shift their focus away from where someone went to university--and there is no sign of that happening anytime soon.

So what other variables could be used if the racial concept is thrown out? Yudell said scientists need to get more specific with their language, perhaps using terms like ancestry or population that might more precisely reflect the relationship between humans and their genes, on both the individual and population level.

Research finds that if employees suffer from high stress, they will be less motivated, less productive and more likely to quit.

Perhaps the reason why so many universities offer their students so little is they know studying at a top university remains a brilliant investment even if you don't learn anything.

If you make clinical predictions based on somebody's race, you're going to be wrong a good chunk of the time, Yudell told Live Science.

If going to university doesn't work out, students pay very little--if any--of their tuition fees back: you only start repaying when you are earning ￡21,000 a year.

If employees respond quickly to their job assignments, the employer is likely to demand more from them.

Having to install a different app for each smart appliance in your home is annoying; it would be nicer if you could manage everything together.

As if that were not enough, a Brazilian C-130 Hercules military transport plane has remained stranded near the runway of Chile's air base here since it crash-landed in 2014.

And if you suspected that the workplace had gotten more stressful than it was just a few decades ago, you're right.

Sternberg would argue it’s not love if you don’t call it love and if you don’t have some desire to maintain the relationship.

So what I’ve done is I’ve taken Sternberg’s three elements of love: intimacy, passion and commitment, and I’ve listed out the different kinds of relationships you would have if you had zero, one, two or three out of the three elements.

So if you have all three of these, intimacy, passion and commitment, in Sternberg’s theory you have love.

Now what’s interesting about the theory is what do you have if you only have one out of three or two out of three? What do you have and how is it different if you have a different two out of three? What’s interesting about this kind of theorizing is it gives rise to many different combinations that can be quite interesting when you break them down and start to look at them carefully.

If children are turning to athletes as role models, it’s in their best interest if their idols are consistent.

He argued that you don’t have love if you don’t have all three of these elements.

We worry most about now because if we don't survive for the next minute, we're not going to be around in ten years' time, says Professor Elke Weber of the Centre for Research on Environmental Decisions at Columbia University in New York.

We found that when we taught participants to ask What if? and How can? questions that nobody present would know the answer to and that would spark exploration, they engaged in better inquiry at the next exhibit − asking more questions, performing more experiments and making better inter pretations of their results.

These students need to build skills and knowledge during college if they are to use their degrees as a stepping- stone to middle-class mobility.

The problem with lighting, if it arises, often doesn't lie in light sources but in their applications.

The incandescent light bulb, invented by Thomas Edison, which came to be the symbol of inspiration, has been developed into hundreds, if not thousands, of forms.

That is because the engineers, designers, regulators, operators, and all of the other skilled people needed for the new energy industry are specialists who have to be trained first ( ' , or retrained, if they are the ones being laid off in some related industry), and education, like any other complicated endeavor, takes times.

So what factors, at the community level, do predict if poor children will move up the economic ladder as adults? What explains, for instance, why the Salt Lake City metro area is one of the 100 largest metropolitan areas most likely to lift the fortunes of the poor and the Atlanta metro area is one of the least likely?Harvard economist Raj Chetty has pointed to economic and racial segregation, community density, the size of a community's middle class, the quality of schools, community religiosity, and family structure, which he calls the single strongest correlate of upward mobility.

Medicare could save hundreds of millions of dollars a year if everyone used the cheaper drug, Avastin, instead of the costlier one, Lucentis.

It's always more of an incentive if you're doing it with other people, she says.

It motivates you more if you know that you've got to provide feedback to a group.

Instead of normalising the undesirable behaviour, the message needs to marginalise it, for example, by stating that if even one person buys yet another SUV, it reduces our ability to be energy-independent.

If, for example, building codes included green construction guidelines, most developers would be too lazy to challenge them.

If you want to change his course, you have only a few choices: you can stop him, transferring ( ' , possibly painfully) some of his kinetic energy ( ' , 动能 ) to your own body, or you can approach alongside and slowly apply pressure to gradually alter his course.

If you try to push a boulder ( ' , 大圆石 ), it pushes you bock.

If we can help to direct students to more of these types of campuses and help students to understand them to be realistic and accessible places, have them apply to these schools at greater frequency and ultimately get in and enroll, we are going to raise the success rate, Rubinoff said, citing a variety of colleges ranging from large state institutions to smaller private schools.

If the Thames were lapping around Big Ben, Londoners would face up to the problem of emissions pretty quickly.

If the CFL should be used for lighting a particular space, or an object within that space, the fixture must be designed to work with that lamp, and that fixture with the room.

He said doctors risked losing the trust of patients if they told patients, I'm not going to do what I think is best for you because 1 think it's bad for the healthcare budget in Massachusetts.

For all the new attention devoted to the 1 percent, a new dataset from the Equality of Opportunity Project at Harvard and Berkeley suggests that, if we care about upward mobility overall, we're vastly exaggerating the dangers of the rich-poor gap.

Erica is proof that a great-grandmother can help to lead the revolution if you get the psychology right — in this case, by matching her enthusiasm for the environment with a fondness for organising groups.

But if it was known that Black people were viewed differently from African Americans, researchers, until now, hadn't identified what that gap in perception was derived from.

And if we're not going to make rational decisions about the future, others may have to help us to do so.

Team management calls for new skills if personnel potential is tobe fully realized.

If we could figure out how to improve the efficiency with which we use energy, we can do a lot of work with the energy that is available.

If a team manager exemplifies such qualities, then the team as a whole would be better able to realize their potential and achieve their objectives.

Charles, as a singer, do you ever make yourself cry when you sing? I wonder if you can tell me a little bit about your job as a radio announcer.

And it may be especially discouraging if you happen to be looking for a job or hoping to change careers right now.

Lingering racism If the Obama effect is positive for African Americans, how is it affecting their white compatriots (同胞)

"We worry most about now because if we don't survive for the next minute, we're not going to be around in ten years' time," says Professor Elke Weber of the Centre for Research on Environmental Decisions at Columbia University in New York.

"As advocates of children's rights, we believe that children should have a voice about what information is shared about them if possible," says Stacey Steinberg, a legal skills professor at the University of Florida Levin College of Law in Gainesville.

"I can't imagine if there's any other acting job in the world where you don't know what show you're in, when you're hired," says voice actor Keythe Farley, who chairs the SAG-AFTRA negotiating committee.

"If they are anywhere near worth their salt as engineers, I bet they are rethinking their threat model as we speak," said Jonathan Zdziarski, a digital expert who studies the iPhone and its vulnerabilities.

"If we can help to direct students to more of these types of campuses and help students to understand them to be realistic and accessible places, have them apply to these schools at greater frequency and ultimately get in and enroll, we are going to raise

"If you look at a lot of low-income communities in the United States, there are programs that are serving them, but they're primarily centered around ‘Let's get these kids' grades up,' and not around ‘Let's get these kids access to the same kinds of oppor

"If you make clinical predictions based on somebody's race, you're going to be wrong a good chunk of the time," Yudell told live Science.

"It's always more of an incentive if you're doing it with other people," she says.

A recent International Labour Organization report says the deterioration of real wages around the world calls into question the true extent of an economic recovery, especially if government rescue packages are phased out too early.

A season in the field will help determine which, if any, of the varieties are ready for commercialization.

And if the sources don't give you an accurate depiction, your stereotype won't be accurate.

And if you suspected that the workplace had gotten more stressful than it was just a few decades ago, you're right.

And just think of how wonderful it would be if you had a live-in robot.

And that's going to affect us, as if we didn't have enough problems on our hands.

And the funny thing is that if you love what you do and are really passionate about it and work really hard, the money kind of comes automatically.

And we also need to plan ahead so that we're in a position to deal with the likely levels of climate change which are already inevitable and even more so too for the levels that are likely if we don't get those global agreements.

And, if you’re not sure, in is always a good idea to check with your primary care provider.

As Jim Loehr and Tony Schwartz have written, if you have too much time in the performance zone, you need more time in the recovery zone, otherwise you risk burnout.

As the great trumpet player, Louis Armstrong said, if you've got to ask, you'll never know.

Barrett wanted to find out if the absence of physical currency does indeed cause a person to spend more, so she decided to conduct an experiment a few months ago.

Because if we aren't, we won't be providing much value in future ecosystems, and that may put in question the foundation for our existence.

Because it's such a pity if you start off on a bright tone on a story and suddenly realize you are talking about some people having been killed in a road crash.

Bottom line, if you think you need more protein in your diet, consider these questions: Are you an extreme athlete; are you recovering from injury or surgery; or are you 60 years or older?

But if the confrontation has crystallized in this latest battle, it may already be heading toward a predictable conclusion: In the long run, the tech companies are destined to emerge victorious.

But if we're talking about the benefits to society, the only thing that matters is what the major enables the student to produce for society.

But most of all we need to keep the long-term perspective in mind: that even if computers will outsmart us, we can still be the most creative.

But put a deadline on the input stage and arrive at a decision, even if it's a decision that doesn't have consensus.

柯林斯高阶英汉双解学习词典释义

CONJ-SUBORD

(表示条件或假设)假如，如果，要是

You use if in conditional sentences to introduce the circumstances in which an event or situation might happen, might be happening, or might have happened.

例句

CONJ-SUBORD

(用于间接疑问句)是否

You use if in indirect questions where the answer is either 'yes' or 'no'.

例句

CONJ-SUBORD

(表示与句子主要部分的陈述稍有不同)即便，纵然，虽然

You use if to suggest that something might be slightly different from what you are stating in the main part of the sentence, for example that there might be slightly more or less of a particular quality.

例句

CONJ-SUBORD

如果…可以的话(通常与can，could, may 或 might 连用,在谈话中礼貌地提出自己的观点、转换话题或打断对方)

You use if, usually with 'can', 'could', 'may', or 'might', at a point in a conversation when you are politely trying to make a point, change the subject, or interrupt another speaker.

例句

CONJ-SUBORD

(用于句首，表示礼貌地请求某人做某事)

You use if at or near the beginning of a clause when politely asking someone to do something.

例句

CONJ-SUBORD

(用于引导从句中较次要的事实)即便

You use if to introduce a subordinate clause in which you admit a fact which you regard as less important than the statement in the main clause.

例句

PHR-CONJ-SUBORD

要是不;即使不

You use if not in front of a word or phrase to indicate that your statement does not apply to that word or phrase, but to something closely related to it that you also mention.

例句

PHR-CONJ-SUBORD

(用于过去时,加强语气)如果真的…

You use if ever with past tenses when you are introducing a description of a person or thing, to emphasize how appropriate it is.

例句

PHR-CONJ-SUBORD

(与过去时连用，引出一个相对合理的理由)即使仅仅为了(或因为)…

You use if only with past tenses to introduce what you think is a fairly good reason for doing something, although you realize it may not be a very good one.

例句

PHR-CONJ-SUBORD

要是…多好

You use if only to express a wish or desire, especially one that cannot be fulfilled.

例句

PHR-CONJ-SUBORD

(表示判断)好像,仿佛,似乎

You use as if when you are making a judgment about something that you see or notice. Your belief or impression might be correct, or it might be wrong.

例句

PHR-CONJ-SUBORD

(表示类比)好像，仿佛，似乎

You use as if to describe something or someone by comparing them with another thing or person.

例句

PHR-CONJ-SUBORD

(强调某物不是真的)好像…一样,仿佛,似乎

You use as if to emphasize that something is not true.

例句

PHRASE

要说真有什么的话;甚至正相反

You use 'if anything' to introduce something which strengthens or changes the meaning of the statement you have just made, but only in a small or unimportant way.

例句

PHRASE

显然不是

You use 'It's not as if' to introduce a statement which, if it were true, might explain something puzzling, although in fact it is not true.

例句

PHRASE

(用于给人建议)如果我是你的话

You say 'if I were you' to someone when you are giving them advice.

例句

英汉词典释义

conj.

如果, 假如

是否

（承认某事可能，但不很重要）即使, 虽然

无论何时,当,每次

（请对方听自己的意见）

（置于 could、may 或 might 之前，以提出建议或客气地打断别人的话）

（与 will 或 would 连用，表示客气地请求）

（用于 ask、know、find out、wonder 等之后，引出两个或以上的可能性之一）是否

（用于表示情感的动词或形容词之后）

（置于形容词之前，引出对比）虽然，尽管

n.

不确定的事, 无把握的事

行业词典

计算机： = input file,【unix】输入文件;= Intermediate Frequency,中频; = Interrupt Flag, 【ASM】中断标志；