205　depend on/upon和rely on/upon

① 表示“信赖，依赖”时，depend on/upon和rely on/upon常可换用。结构为：

depend on/rely on sb./sth.

depend on/rely on sb. to do sth.

We can depend on/rely on her words. 我们可以相信她的话。

He depends on/relies on you to help him. 他依靠你帮助他。

How could you depend on his promise？你怎么能相信他的许诺呢？

The girl no longer depends upon her parents. 这小女孩已经不依靠父母了。

提示

rely on 语气比depend on重，多以人作主语。

A man should rely upon his own powers in the struggle of life. 一个人在生活的斗争中应当依靠自身的力量。

② depend on还可以表示“以……而定，由……而定，取决于”，这时不可用rely on。

It depends on yourself. 这取决于你自己。

Good health depends on good food，exercise and getting enough sleep. 身体的健康要靠良好的食物、锻炼和充足的睡眠。

③ depend用于It all depends或That depends结构中，意为“很难说，得看情况”，这时不可用rely。

Can you finish the work before Sunday？It all depends. 你能在星期天前完成这项工作吗？这要看情况。

I don't know whether we'll have a picnic. It depends on the weather. 我不知道我们是否去野餐。那得看天气。