The aircraft vanished without（）

Shall we request the chairman（）our suggestion again?

The price they offered for my old car was so low that I（）it down.

Since we can't hear you at the back of the hall, you'll have to（）your voice.

An explosion is a sudden increase in amount（）

I expected a bigger payment, but I suppose you have to be（）for small mercies.

Nobody knows how long and how seriously the shakiness（不穩(wěn)定） of big businesses will （） down the economy.

（）students often find it difficult to live in China at first.

I was（）than angry when I saw how they'd ruined the landscape.

Our department（）courses in several foreign languages.