both的位置：
（1） 在be的后面
（2） 在实意动词前面 （往往用they both ,you both, wei both)
（3） 在情态动词，助动词后面
请看下面的例句：
①They are both very healthy. 他们俩都很健康。
②We are both interested in English.他俩都对应于感兴趣。
①We both have too much work to do. 我们俩有太多的工作要做。
②You both had a good time last might,didn't you? 你们俩昨晚玩得很愉快，是吗？
③They both went to Beijing last week. 上周他们俩都去了北京。
①Don't thank me. You must both thank him!
别谢我。你们俩必须感谢他！ must=必须 情态动词
②We have both passed the exam. 我们俩都已经通过了考试。have=已经 助动词
