A. where is his motherB. where his mother isC. where wa……

单项选择题The secretary tried to （） the smoke by opening a window of the meeting room.

A. deface
B. detect
C. discriminate
D. dissipate

单项选择题All children are avid （） praise.

A. on
B. for
C. with
D. at

单项选择题—When （）you（）to learn to skate —Five years ago.

A. do; start
B. will; start
C. had; started
D. did; start

单项选择题—Thanks for your help. —（）

A. No, thanks
B. Let me see
C. It doesn't matter
D. That's OK

单项选择题—（） will you come back7 —In an hour.

A. How soon
B. How often
C. How far
D. How long