i don't know what books i should buy for my son 的同义句答案必须是这种形式:i don't know___ ___ ___ ___for my son

i don't know what books i should buy for my son 的同义句答案必须是这种形式:i don't know___ ___ ___ ___for my son
i don't know what books i should buy for my son 的同义句
答案必须是这种形式:i don't know___ ___ ___ ___for my son

i don't know what books i should buy for my son 的同义句答案必须是这种形式:i don't know___ ___ ___ ___for my son
I don't know what books to buy for my son
在这里用了“疑问词+不定式”作宾语,相当于原句子的宾语从句,这是初中的重点呀

i don't know_what__ _books__ _are__ suitable__for my son