when

英[wen]美[wen]

conj.当…时，一；

pron.什么时候；

adv.什么时候，在那时，当时；

英语六级真题

We need very broad participation to fully address the global tragedy that results when countries fail to take into account the negative impact of their carbon emissions on the rest of the world.

The reason is that when carbon is priced, those emissions reductions that are least costly to implement will happen first.

The British traveler Charles Thompson spoke for many Grand Tourists when in 1744 he described himself as being impatiently desirous of viewing a country so famous in history, a country which once gave laws to the world, and which is at present the greatest school of music and painting, contains the noblest productions of sculpture and architecture, and is filled with cabinets of rarities, and collections of all kinds of historical relics.

Middle school is a crucial period when students may become keenly interested in advanced mathematics.

At a time when young beauty shoppers are often turning to Sephora or Ulta instead of department store beauty counters, Macy's hopes Bluemercury will help strengthen its position in the category.

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.

When we ask teens to choose a hero, they usually select an older family member rather than a remote public figure.

When this water is used for agricultural irrigation, farmers risk absorbing disease-causing bacteria, as do consumers who eat the produce raw and unwashed.

When the health insurance industry was still cooperating in reform efforts, its trade group offered to provide standardized forms for automated processing.

When I was in high school, dozens in my class alone would have answered differently.

This is really about trying to cut through the confusion that consumers have when they are buying a product and that businesses have when they are selling a product, said Jon Leibowitz, chairman of the commission.

They speak with Mom or Dad when they have a problem.

The revisions come at a time when green marketing is on the rise.

The lawsuits said that the label was misleading because it gave the impression that the products had been certified by a third party when the certification was the company's own.

Some are turning to the Internet, which is cheaper and offers concrete measurements like click-through rates— especially important at a time when marketing budgets are tight.

Measuring emissions is not a precise science, particularly when it comes to issues surrounding land use; not all nations have released up-to-date data, and in any case, emissions from some sectors such as aviation are not included in national statistics.

It is fine and healthy for teens to cultivate their personal interests, and it is good news when young people enjoy harmonious relations with their family and friends.

It is also troubling that voting rates among our youngest eligible voters—18- to 24-year-olds—are way down: Little more than one in four now go to the polls, even in national elections, compared with almost twice that many when 18-year-olds were first given the vote.

Interactive television advertising is successful when incorporated into situation comedies.

In fact, other recent studies have found there has never been a time in American history when so small a proportion of young people have sought or accepted leadership roles in local civic organizations.

For example, only one boy said he would like to be president when he grows up.

As I said, structural unemployment isn't a real problem, it's an excuse—a reason not to act on America's problems at a time when action is desperately needed.

You know, one of the first things I like to tell people when they ask me about the supplements, is that a lot of them are promoted as a cure for your memory, but your memory doesn’t need a cure.

The other thing is that a lot of these supplements aren’t necessarily what they claim to be, and you really have to be wary when you take any of them.

Too many workplace policies effectively prohibit employees from developing a healthy work-life balance by barring them from taking time off, even when they need it most.

The ROWE participants were allowed to freely determine when, where and how they worked – the only thing that mattered was that they got the job done.

It's a dramatic endorsement for a technology most people think about only when their smartphone goes dark.

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.

Harvard Business School professor Leslie Perlow explains that when people feel the pressure to be always on, they find ways to accommodate that pressure, including altering their schedules, work habits and interactions with family and friends.

For example, when asked whether they would buy a new smartphone this year, only 48 percent said yes – a six-point drop from 2015.

But even when employees are given paid time off, workplace norms and expectations that pressure them to overwork often prevent them from taking it.

And when it comes to the hyper-connected super-smart world that technology firms are painting for us, it seems that consumers are growing more uneasy about handing over the massive amounts of consumer data needed to provide the personalized, customized solutions that companies need to improve their services.

When they returned home, their droppings end up all around their nesting sites, including in nearby ponds.

When the molten rock of the earth’s core forced its way to the surface to form the throat of a volcano, as the centuries passed, the rock cooled and hardened, shrinkingand cracking into long columns.

When I teach in classroom, we often end up talking about things like success and what leads to success.

We can’t expect kids to turn off that admiration when the same person is selling sugar.

Today, I’d like to talk about what happens when celebrity role models get behind healthyhabits, but at the same time promote junk food.

The pollutants in the ponds appear to come from fish that fulmars eat when they’re out on the ocean.

The legend says that when seven girls were attacked by bears, they took refuge on top of a small rock, and they appealed to the Rock God for help.

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.

And we create opportunity for assessment and intervention, to help clients and communities cope effectively with the reality and change that reality when necessary.

When you hear people speaking of making a rapid transition toward any type of energy, whether it is a switch from coal to nuclear power, or a switch from gasoline-powered cars to electric cars, or even a switch from an incandescent to a fluorescent light, understanding energy system inertia and momentum can help you decide whether their plans are feasible.

When we can't actually remove the source of our fear, we tend to adapt psychologically by adopting a range of defence mechanisms, says Tom Crompton, change strategist for the environmental organisation World Wide Fund for Nature.

When people find they are powerless to change a situation, they tend to live with it.

When investors put up money to build, say, a nuclear power plant, they expect to earn that money back over the planned life of the plant, which is typically between 40 and 60 years.

When a technology is deployed, its impacts reach far beyond itself.

When Nijay Williams entered college last fall as a first-generation student and Jamaican immigrant, he was academically unprepared for the rigors of higher education.

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.

They underestimate themselves when selecting a university, said Dave Jarrat, a marketing executive for Inside Track, a for-profit organization that specializes in coaching low-income students and supporting colleges in order to help students thrive.

Take costs into account when making treatment decisions.

By far the biggest type of momentum that comes into play when it comes to changing our energy systems is economic momentum.

Another type of momentum we have to think about when planning for changes in our energy systems is labor- pool momentum.

When teamsconsist of experienced employees from hierarchical organizations, who have been conditioned to traditional organizational culture, cooperation may not occur naturally, it may need to be created.

The best form of advertising is probably word-of-mouth advertising which occurs when people tell their friends about the benefits of products or services that they have purchased.

He believes that team corporation results when members go beyond their individual capabilities, beyond what each is used to being and doing.

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.

"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.

"They underestimate themselves when selecting a university," said Dave Jarrat, a marketing executive for Inside Track, a for-profit organization that specializes in coaching low-income students and supporting colleges in order to help students thrive.

"This is really about trying to cut through the confusion that consumers have when they are buying a product and that businesses have when they are selling a product," said Jon Leibowitz, chairman of the commission.

"We as a society need to understand that, when we don't punish lying, we increase the probability it will happen again," Ariely says.

"What our study suggests is that teenagers learn more quickly and more effectively when their peers are present than when they're on their own,'' Steinberg says.

"When people experience decision fatigue—when they are tired of making choices—they have a tendency to choose to go with the status quo 现状," he says.

"When we can't actually remove the source of our fear, we tend to adapt psychologically by adopting a range of defence mechanisms," says Tom Crompton, change strategist for the environmental organisation World wide Fund for Nature.

A high-tech test that can tell when a person is not telling the truth sounds too good to be true.

A new study from michigan State University, though, argues that all students—including high achievers—see a decline in performance when they browse the Internet during class for non-academic purposes.

About that same time and throughout adulthood, the information you receive, especially when ideas are repeated in association with goals and achievements you find attractive, also refines your attitudes.

Algorithms that were right 95% of the time when they were dealing with a 13,000-image database, for example, were accurate about 70% of the time when confronted with 1 million images.

And now, for the lighter side of the news, Europe is setting an example for the rest of the world, when it comes to food waste.

And she criticizes me in exactly the same way she did when I was first unpublished and I was starting.

And we are less likely to lie when we have moral reminders or when we think others are watching.

And when it comes to the hyper-connected super-smart world that technology firms are painting for us, it seems that consumers are growing more uneasy about handing over the massive amounts of consumer data needed to provide the personalized, customized so

And when something sounds too good to be true, it usually is.

And when we get off the plane, instead of being depleted, we feel recovered and ready to return to the performance zone.

And while the Portuguese took part in the trade, ferrying nuts down the coast along with other goods, by 1620, when English explorer Richard Jobson made his way up the Gambia, the nuts were still peculiar to his eyes.

Another type of momentum we have to think about when planning for changes in our energy systems is labor-pool momentum.

Apple's stance on these issues emerged post-Snowden, when the company started putting in place a series of technologies that, by default, make use of encryption to limit access to people's data.

As constant travelers and parents of a 2-year-old, we sometimes fantasize about how much work we can do when one of us gets on a plane, undistracted by phones, friends, or movies.

At a time when natural history was a valuable tool for discovery, Merian discovered facts about plants and Insects that were not previously known.

Because when the dust settles, people are going robe pretty much what they are.

Brittleness remains a problem when building steel structures in cold conditions, such as oil rigs in the Arctic.

But ￡3,000 trips cannot be justified when the average income for families with children is just over ￡30,000.

But a recent study seems to point to the fact that when matter and anti-matter were first created, there were slightly more particles of matter, which allowed the universe we all live in to form?

But convincing open-minded dairy people is actually not that hard, when you look at the economics.

But decision fatigue goes away when you are making the decision for someone else.

But even when employees are given paid time off, workplace norms and expectations that pressure them to overwork often prevent them from taking it.

But some companies are realizing that placing the burden of recycling entirely on the consumer is not an effective strategy, especially when tossing something away seems like the easiest and most convenient option.

But students who surfed the web during class did worse on their exams regardless of their ACT scores, suggesting that even the academically smartest students are harmed when they're distracted in class.

But surely everyone reading this has had times when you lie in bed for hours, unable to fall asleep because your brain is thinking about work.

But then when you see a picture, the idea finally clicks?

But what happens when new players emerge, who don't have deep roots within the existing culture?

But when our diverse team of researchers from six different disciplines and eight different countries began to review what was known, we were shocked that only a dozen previous studies had been done, including one we ourselves completed on language divers

But when scientists had their subjects play a game一in which they won money by deceiving their partner, they noticed the negative signals from the amygdala began to decrease.

But when two H-bots became imperiled, the robot choked 42 percent of the time, unable to decide which to save and letting them both.

But, he says extreme events become disasters only when people fail to prepare for them.

Charles, as a singer, do you ever make yourself cry when you sing?

Common research has long held that talking themselves through a task helps children learn, although doing so when you'v apparently matured is not a great sign of brilliance.

Dehydration is also a risk when you eat too much protein.

Europeans did not know of them until the 1500s, when Portuguese ships arrived on the coast of what is now sierra Leone.

Even Hillary Clinton says that when it comes to college, Costs won't be a barrier.

Even in June of 2007, when the economy was still moving ahead, job growth was only 132,000, while turnover was 4.7 million!

柯林斯高阶英汉双解学习词典释义

QUEST

(用于疑问句)什么时候，何时

You use when to ask questions about the time at which things happen.

例句

CONJ-SUBORD

(表示两事同时发生)在…时，当…时

If something happens when something else is happening, the two things are happening at the same time.

例句

CONJ-SUBORD

(引导从句，表示某事发生于另一活动、事件或情形期间)在…的过程中

You use when to introduce a clause in which you mention something which happens at some point during an activity, event, or situation.

例句

CONJ-SUBORD

(引导从句，说明主句动作已经发生或将要发生时的情况)其时

You use when to introduce a clause where you mention the circumstances under which the event in the main clause happened or will happen.

例句

CONJ-SUBORD

(尤用于动词和形容词后引导从句，表示某事发生的时间)什么时候,何时

You use when after certain words, especially verbs and adjectives, to introduce a clause where you mention the time at which something happens.

例句

PRON-REL

(用于引导从句，限定或指示某事发生的时间)…的时候

You use when to introduce a clause which specifies or refers to the time at which something happens.

例句

CONJ-SUBORD

(用于引出某个观点、评论或问题的原因)既然，考虑到

You use when to introduce the reason for an opinion, comment, or question.

例句

CONJ-SUBORD

(用于引出使句子的其他部分显得让人吃惊或不大可能的事实或评论)虽然，然而,可是

You use when in order to introduce a fact or comment which makes the other part of the sentence rather surprising or unlikely.

例句

英汉词典释义

adv.

什么时候

（用于时间的表达方式之后）在那时, 其时

其时；当时；当场

conj.

在…时, 当时

如果, 要是

既然, 考虑到

在…之后

在任何…时候

一…就；刚…就

虽然；然而；可是

pron.

什么时候

那时

英英词典释义

Adverb

1. as soon as;