- Change these sentences into the Present Perfect Passive, putting the verbs into the correct forms.
用动词的正确形式将下面的句子变成现在完成时的被动语态。
- Students say out the three forms of some regular and irregular verbs by giving the infinitives.
引入竞争机制，说出规则与不规则动词的三种形式，巩固被动语态中过去分词的正确使用。
