不定式作謂語
（2）在feel（一感）,listen to,hear（二聽）,let,make,have（三讓）,look at,see,watch,notice（四看）等詞之后接不帶to的不定式作賓語補(bǔ)足語,強(qiáng)調(diào)動(dòng)作的完成過程；它們作被動(dòng)句的謂語時(shí),to要補(bǔ)上.如：
I heard her sing today．She sang wonderfully．今天我聽見她唱歌了,她唱得非常精彩.
She was heard to sing today．今天有人聽見她唱歌了.（這句heard是作表語嗎?)
She is often heard to sing this song（by us）．我們經(jīng)常聽見她唱這首歌