be动词的用法:1.表示"是"当联系动词,后常接形容词或名词.如:I am a student.You are a techer .He is tall .当然,其它接动名词,不定式,副词,介词短语也有.2.当助动词,与其它词一起构成被动语态,或进行时态等:He was praised yesterday .I am doing my homework now .
