1.由少数及物动词转化来的不及物动词(sell, clean, wash, cut, drive, wear, write等),当句子的主语为物时,可用主动形式表被动意义。The car drives well.The cloth washes easily.2.在be worth doing, need doing中,主语是物,doing表示被动意义。The book is worth reading.The tree needs watering.3.形容词 cheap, dangerous, important, comfortable, interesting等接不定式做状语时,不定式的主动形式表被动意义。The old lady is easy to get along with.The question is difficult to answer.4.感官动词look, sound, taste, smell, feel等,主动语态表被动意义。You look unhappy.