If the two media have really different densities, like air and water, then most of the energy is going to be reflected back, very little of it will keep going and get transmitted into the new medium.

而如果这两种介质的密度相差较大，就像空气和水那样，那么大部分的能量将会折射回来，只有一小部分会继续传播进入到新的介质中。

youdao

If I run out of things to say or write, I will simply repeat the last word to keep the momentum going.

如果我脱离要说或者要写的东西，我会简单的重复最后一个字，让这个趋势走下去。

youdao

"The only way we're going to keep our soldiers fit to fight, if you will, is to make sure it is a holistic approach, not just the physical but mental readiness, " Lt.

我们保持士兵适合作战的途径就是保证他们全身心的达到那种状态，不仅仅只是生理或是心理上的准备就绪。

youdao

But I have been trying to keep abreast of what is going on and I will do the best I can."

VOA: standard.2009.06.30

And just to keep the rhythm going, we will have a test on Tuesday, the weekly quiz.

保持节奏，我们周二将有场考试，周测。

麻省理工公开课 - 固态化学导论课程节选

Isner looks like he's ready to fall, he's completely done and yet he still had the will to keep this thing going.

BBC: John McEnroe on Isner and Mahut Wimbledon epic

Access to funds will become easy after the struggle to keep going after the last few years.

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When the hammer comes down, if the chamber is empty, the ECB and Mr. Supposedly Tough Guy (or gal, in the case of Christine Lagarde), the IMF, will give the banks enough money to keep the game going.

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