sink or swim

[美俚]关健的决定；

决定胜败的一举

Whether he will invest his last sum in that project is a case of sink or swim for him.

他是否把他的最后一笔钱投于那个项目，是决定成败的关健。

注解：
sink指下沉，swim指游泳，浮水；

sink or swim指要么沉下去，要么奋力游上来，喻指生死、成败的关健决定。

give someone the eye

[美俚]向某人抛媚眼；暗示

When a young man is giving her the eye, Mary never gets too excited and she knows better not to take it too serious.

当年轻男子对她抛媚眼时，玛丽总是很矜持，并且更懂得别太往心里去。

注解：
eye意指眼睛，目光；

to give someone the eye系指某人，喻指眉目传情，暗送秋波。