it is hard to understand this kind of Books 去掉形式主语后,下列哪一种是对的?改形式主语有什么要求Books of this kind is hard to understandTo understand this kind of Books is hard

It is hard to It is hard to wait It is hard to please It is hard to select! It is hard to study English g______well. it is time to study hard! why it is so hard to do It is hard to bear with criticism. it is hard to say 什么意思? It is hard to be a soldier. 是i find it hard to say 还是i find it is hard to say I found it hard to understood为什么不是I found it is hard to understood it is hard to+Ving还是to do sth to explain it to him is hard同义句 ‘It is hard to reciprocate equal love to each other. it is too hard For a time his grandmother found ___accept his new idea.A.hard B.it hard C.it is hard to D.it hard to it is hard to say goodbye同义句 _ _ _ is hard