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

In a large saucepan, combine milk, vanilla extract, and 1 tablespoon butter or margarine. Bring to a boil over medium heat, then remove from burner.

在一个大煮锅里，将牛奶、香草香精和1汤勺黄油或人造黄油混合。中火加热，烧开后从炉灶上取下。

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The researchers then took neurons from the excised brain matter and placed them in a blood-rich culture medium.

研究人员随后从切除的脑组织中提取神经元，并将其置于富含血液的培养基中。

youdao

"But we also have to recognize that if markets are skittish and don't have confidence that we can tackle the tough problems of our medium- and long-term debt and deficits,then that also is going to undermine our recovery."

VOA: standard.2010.06.27

You've probably seen agar plates, if you smear a solution that's contaminated with bacteria on it, then that bacteria will grow on this agar rich medium and you'll get many, many copies of the bacteria that you've smeared at low density onto the plate.

你们大概见过琼脂培养基,如果将有细菌的溶液涂抹在培养基上,细菌就会在富含琼脂的培养基上生长,你会得到许多许多细菌,即使你只涂抹了低浓度溶液

耶鲁公开课 - 生物医学工程探索课程节选

And then people kept thinking they had to reinvent the medium.

然后人们会想要再重新创作。

学习制作动画 - SpeakingMax英语口语达人

And you made a distinction between the short-term focus on jobs and then the medium-term focus on getting the fiscal house in order.

WHITEHOUSE: Press Briefing

There is recognition that if unemployment is to fall then small and medium-size companies need to be helped.

BBC: Europe is afraid - the battle for new jobs

Add the sherry or Madeira and brandy and beat on low speed until incorporated, then beat on medium-high speed until the mixture is smooth and fluffy, 1 to 2 minutes.

NPR: Two Centuries of 'Baking in America'