短语讲解：

1. They can make that sound, non-stop, for hours at a time.

at a time 依次， 逐一， 每次
例句：Can I borrow two books at a time?
我可以一次借两本书吗？

2. “We will reveal very fundamental mechanisms of just how this hormone in fact controls daily sleep/wake cycles in all animals.”

in fact 事实上; 实际上
例句：You have to admit that you are, in fact, in difficulties
你不得不承认，你事实上是陷入了困境。

3. Bass said they thought the sound came from either an underwater power line, a nearby water treatment center, a U.S. Navy experiment, or maybe even beings from other planets.

come from 源自; 来自某处; 出生于
例句：He's just come from the countryside.
他刚从乡下来。
 4/5   首页 上一页 2 3 4 5 下一页 尾页