不定式的主动和被动
1. 不定式修饰的名词或代词和不定式逻辑上构成主谓关系时,不定式往往用主动形式。如:
Do you have a knife to cut the watermelon?( A knife cuts the watermelon.)
2. 不定式和它前面所修饰的名词后代词构成逻辑上的动宾关系,又和该句主语构成逻辑上的主谓关系时,不定式常用主动式。如:
She has a sister to look after.(She looks after her sister)
3. 不定式作表语形容词的状语,和句子主语构成逻辑上的动宾关系时,不定式多用主动形式,这是因为人们往往认为形容词后省去了for sb.。如:
This book is difficult to understand.
This kind of fish is nice to eat.
4. 在there be 结构中,当说话人考虑的是必须有人去完成某件事时,不定式用主动形式;如果说话人强调的事情本身必须被完成,则用被动形式。如:
There is a lot of work to do. (Someone has to do the work.)
There is a lot of work to be done. ( The work has to be done.)
责任编辑:sealion1986