1 . Great changes ______(take) place in our city in the past 10 years. (所给词的适当形式填空)

3 . This is the first time that we ___________(exchange) our views on these problems and I hope this is not the last. (所给词的适当形式填空)

4 . It’s the third time I___________(catch) a fever this year. (所给词的适当形式填空)

5 . —How soon will you finish the work?
—In a week. We________ about 80% of the work so far.

A．completed

B．will complete

C．have completed

D．are completing

6 . Many parts of China ______________ (see) very heavy rainfall in the past few days. (用所给词正确形式填空)

7 . It is clear that, to date, these health care products ____________(target) at old people. (所给词的适当形式填空)

8 . The number of firms selling computers in those regions        over the last few years.

A．are falling

B．have fallen

C．has fallen

D．is falling