A、are they
B、aren’t they
C、were they
D、have they
答案：A
A、are they
B、aren’t they
C、were they
D、have they
答案：A
A. close
B. to close
C. closing
D. closed
A. as though
B. even if
C. as
D. since
A. run; to fill
B. running; filling
C. running; to fill
D. ran; filling
A. the
B. a
C. an
D. /
A. that
B. where
C. which
D. when
A. are too many rooms
B. are too much room
C. are plenty of rooms
D. is plenty of room.
A. paid off
B. paid back
C. carried out
D. paid for
A. on which
B. where
C. in that
D. during which
A. it
B. that
C. it is
D. that is
解析：这道题考察的是代词的用法。正确答案是A: it。
在这个句子中，"it" 作为形式宾语，代替了后面的不定式动词短语"to learn English grammar"。所以句子的正确表达应该是"I found it difficult to learn English grammar."，意思是"我发现学习英语语法很困难"。
A. get up
B. getting up
C. gets up
D. got
