Keep quite when you reading in the library.

在图书馆里读书要保持安静。

No cycling keep of keep quite take a walk look around?

禁止骑自行车使不接近保持安静散步向四周看

I told him to keep quite about that Mac stuff and just let me do the talking.

我告诉他不要说关于Mac材料，让我说就行了。