In some places, wave peaks add up to become very large; in other places, they completely cancel out.

在一些地方，波峰积累起来变得非常大；在另一些地方，它们完全抵消了。

And the frequency is how many times a wave peaks in a given second.

频率是波在给定秒内达到峰值的次数。

So if you double the amplitude of a wave's peaks, it gets four times as bright.

因此，如果将波峰的幅度加倍 ，它的亮度会增加四倍。

They looked at the period from the very start of the pandemic, in early 2020, to when the Delta wave peaked in the fall of 2021.

他们观察的时间段，从疫情最早期的 2020 年初，一直到德尔塔浪潮达到高点的 2021 年秋天。

The UK economy shrank an unprecedented 20.4 percent in the second quarter of this year between April and June confirming an official recession as the economy shut down during the first wave peak of the coronavirus pandemic.

在今年4到6月的第二季度 英国经济史无前例地萎缩了20.4% 确认经济正式衰退 此前在冠状病毒大流行的第一波高峰期经济停摆。