英文文法-代名詞請益2013/1/14 - 考試

不好意思,小弟才疏學淺，想請教各位大大幾題英文文法試題
(出處:王怡華-文法練習1000題)

1.He found------difficult to support his family.
(A)this (B)it (C)that (D)such
答案:(B),不明白為何選它


2.He lived in poverty, and he could not help------.
(A)so (B)such (C)it (D)that
答案:(C),為何不可選(D)?


3.You must help him, and----------immediately.
(A)so (B)such (C)it (D)that
答案:(D),為何不可選(C)? 請問何時可用it來代替前面的句子?

4.Is Prof.Lee very sick? I'm afraid-------.
(A)so (B)that (C)this (D)to
答案:(A),不明白為何選它?

5.Aaything wrong? There was no objection on the part of ------present.
(A)these (B)that (C)those (D)who
答案:(C),為何不可選(A)?

6.Please see to it----the door is locked.
(A)and (B)but (C)that (D)if
答案:(C),想選(A),但2邊時態又不同..不明白為何選它?



萬分感謝~~

--