短语讲解：

1. Malaysia’s leader has confirmed that a piece of an airplane wing found on an Indian Ocean island belonged to Malaysia Airlines Flight MH370.

belong to 属于
例句：I belong to no party.
我不属于任何派别。

2. U.S. military officials said an unmanned aircraft carried out the cross-border strike Wednesday.

carry out 履行
例句：No matter what we do, we must carry out our duties.
无论干什么工作,我们都应履行自己的职责。

3.It would be good for the United States.

be good for 值得，有效; 利于
例句：Do it up. It'll be good for you.
把它喝完，它对你有益。