Man was, is and always will be trying to improve his living conditions.

我們認為節(jié)約用水非常重要。

I thought you might be tired, （） is why I decided to help you.

There is nothing so admirable as a man whose sacrifices his life and happiness for others. 

我想知道他把表送給誰了。

事實勝于雄辯。

An idle youth, a needy age.

The doctor will get more practice out of me than out of ten ordinary patients.

The wound soldier made an effort to stand up, but the general stopped him.

Cars turn into dead weapons when they are driven carelessly.