4. 不定式的完成被动式
　　当不定式的逻辑主语是这个不定式所表示的动作的承受者，且不定式的动作发生在谓语动词的动作之前，不定式要用完成被动式，在句中可作主语，宾语或构成复合宾语，复合谓语。

　　The forest fire is reported to have been put out last night.
　　It is supposed to have been finished without referring to any reference books.