一发出信号就...

Studies in animals and humans overthe last four years have provided compelling evidence that leptinmay be a neurohumoral mediator capable of signalling between theextent of nutritional intake and body fat store to the centralnervoussystem.

过去几年在动物和人身上的研究提供了强有力的证据表明：瘦素可能是一种神经体液调质，就营养摄入与脂肪贮存程度向中枢神经系统发出信号。

It made squawking sounds about every half hour to indicate it wanted to be fed - a positive sign, researchers said.

大约每过半个小时它就会发出刺耳的叫声提醒人们给它喂食。研究者们称，这是一种积极的信号。

A guard was about to signal his train to start when he saw an attractive girl standing on the platform by an open door, talking to another pretty girl inside the carriage.

就在一位列车员即将发出使列车出发的信号时，他注意到了一位迷人的女孩正靠着列车门站在站台上，同车厢里面的另外一位漂亮女孩交谈着。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。