do you think it necessary to do my homework

问题描述:

do you think it necessary to do my homework
Do you think it necessary to do my homework
为什么不是Do you think it is necessary to do my homework

这两个句子都是对的,意思也相同.不同的是第一句中it在句中做形式宾语,后面的不定式是真正的宾语,第二句it及以后的部分做think 的宾语,it在宾语从句中做主语.