She found (to convince him) difficult. 主 谓 宾 宾补 She found (that it is difficult to convince him). 主 谓 宾从(that可省,宾从中 it 是形式主语,真正的主语是不定式to convince him) She found (that可省) to convince him is difficult. 带不带is决定了这是一个简单句还是复合句 没有is,就是一个简单句, 不定式作宾语,difficult是宾语补足语 有is,就是一个主从复合句,found带一个宾语从句,不定式作宾语从句的主语
it做形式宾语,代替真正宾语:to convince him 当宾语是不定词或名词子句时,因为宾语过长,常用形式宾语it代替,写成Vt+it+形容词+ 不定词或名词子句,来使句子显得更加工整。比如: [He made it clear what he intended to do.] 或[He made what he intended to do clear.] [i ...