单项选择题
When mother entered the bed room, little Shelly pretended（）asleep.
A.having fallen B.to be falling C.being fallen D.to have fallen
单项选择题 — Do you think I could borrow your calculator? —（）
单项选择题 Don't disturb me. I（）letters all morning and have written ten so far.
单项选择题 Mr. Smith（）a most important part in the development of our city.
