[考點辨析]be used for/as/in/to do

（1）be used for doing sth. 意為“（被）用來做某事”，強調用途或作用，相當於be used to do sth.

Knives are used for cutting things.

=Knives are used to cut things.

刀子被用來切東西。

（2）be used as … 意為“(被)用作……”，強調被當作工具或手段來用。

Mobile phones are used as tools which make people communicate easily.

手機被用作人們之間輕鬆交流的工具。

(3)be used to do sth. 意為“(被)用來做某事”，強調目的。

Computers can be used to do many things.

電腦可以用來做許多事。

(4)be used in … 意為“被用在……裡”。

The hat was used in the play in the past.

這個帽子在過去被用在戲劇中。

Let's have a try.

謝謝！