I think it is helpful to buy an English dictionary.(同义句转换)

问题描述:

I think it is helpful to buy an English dictionary.(同义句转换)
I ___ ___ ___ buy an English dictionary.注:要填三个空.

think it helpful, 形式宾语+ 宾补,即不定式短语替代宾语从句,结构不同,意思一样.