7．Experts have been warning ________ of the health risks caused by passive smoking.

A．at a time B．at one time C．for some time D．for the time

8．Cathy is taking notes of the grammatical rules in class at Sunshine School, where she ___________ English for a year.

A．studies B．studied C．is studying D．has been studying

9．With the help of high technology, more and more new substances ______ in the years.

A．discovered B．have discovered C．had been discovered D．have been discovered

10. -I have got a headache.

-No wonder. You_________ in front of that computer too long.

A. work B. are working C. have been working D. worked

11. The unemployment rate in this district_______ from 6% to 5% in the past two years.

A. has fallen B. had fallen C. is falling D. was falling

StepV Homework 完成练习册31、32页

StepVI总结反刍：

3. Now that she is out of job, Lucy ___ going back to school，but she hasn't decided yet.

A. had considered B. has been considering

C. considered D. is going to consider

4. -______ you ______ him around the museum yet?

-Yes. We had a great time there.

A. Have ; shown B. Do ; show C. Had; shown D. Did; show

5. -Hi, Tracy，you look pale.

-I am tired. I _______ the living room all day.

A. painted B. had painted C. have been painting D. have painted

6.-Why, Jack , you look so tired !

　-Well, I _______the house and I must finish the work tomorrow.

A. was painting B. will be painting C. having painted D. have been painting

7. Joseph ______to evening classes since last month , but he still can't say " What's your name? " in Russian.

A. has been going B. went C. goes D. has gone

8. Mother wanted to be a good provider , a role she _____since her marriage to Father.

A. shoulders B. shouldered C. is shouldering D. has been shouldering

9. -Why do you want to work for our company ?