1. Expression：have a wolf in the stomach

Explanation：To be hungry to death. （饿极了）

Example：My boy, I think that you have a wolf in the stomach. Breakfast will be ready as soon as the sun's up and we'll have a piping hot one. Make yourself easy about that!

好家伙，我想你一定饿极了。 太阳一出来，早饭就好了。咱们就可以吃上一顿热气腾腾的饭，你尽管放心吧！（汤姆历险记）

They have a wolf in the stomach after a day's walk that they made very short work of their supper.

他们走了一天路，饿极了，因此他们很快就把晚餐吃完了。

2. Expression：keep on the down-low

Explanation：To keep something secret; not tell other people about something. （保密）

Example：Her parents wouldn’t approve of our relationship so we keep it on the down-low.

她的父母不会赞成我们之间的关系，所以我们不告诉他们。

Keep this on the down-low, Janet is planning to break up with Kevin next week.

不要告诉别人——Janet准备下周和Kevin分手。

This meeting and the entire arrangement are supposed to be kept on the down-low.

这次会议以及整个的安排应该都是保密的。

3. Expression：keep one’s ear close to the ground

Explanation：To listen for any indication of what is happening or will happen. （对一事态极其关注，密切留意）

Example：I know Kim is keeping her ear close to the ground in case word gets out about the promotion.

我知道金姆一直在密切注意事态的发展，以防有关晋升的消息传出去。

A: I'm not sure what's going to happen with this merger, so I'm keeping an ear close to the ground.

我不知道这次合并会有什么结果，所以我会密切留意。

B: Please let me know if you hear anything.

如果你听到什么，请告诉我。

A：I really want to be a succesful reporter, but I don’t know what to do. Can you give me some advice?

我真的想成为一名成功的记者，可是不知从何做起，你可以给我一些建议吗？

B：Well, to succeed as a reporter, you should first of all keep your ear close to the ground.

嗯，要想成为一名成功的记者，你首先要做到的就是对某些事态保持高度的关注。