It is diffcult for him to do it 谓语是is diffcult吗 那for只是介词吗
问题描述：
It is diffcult for him to do it 谓语是is diffcult吗 那for只是介词吗
答
It is diffcult for him to do it.
此句完全正确,你说得也非常对!谓语是is diffcult,是系表结构做谓语；for是介词；