13、 (2011年潍坊质量监测)When people cut down big trees，new trees should be planted.________they will have no trees to cut down in the future.

A．If not                           B．If so

C．If no so                        D．If don’t

12、 (2010年海南五校联考)I have been living in Haikou for 10 years，but seldom________so lonely as now.

A．have I felt                                   B．I have felt

C．had I felt                                    D．I had felt

11、 (2010年湖北部分重点中学高三第一次联考)Many a writer of newspaper articles ________ to writing novels.

A．has turned                           B．have turned

C．being turned                        D．are going to turn

10、 (2011年西安八校联考)—Mom，have you washed my clothes?

—No.I’m busy，but I________them for you now.

A．wash                           B．am washing

C．will wash                     D．would wash

9、 (2010年青岛市第二次模拟)—Where is your uncle’s home?

—In New York.But he________in Boston for four years.

A．has lived                       B．lived

C．had lived                      D．had been living

8、 (2010年济南4月模拟)—Can you give some advice on what I said just now?

—Sorry.My mind________.

A．is wandering                 B．was wandering

C．has wandered               D．has wandered

7、 (2011年陕西宝鸡检测)Mary，I should tell you it is the third time that you________.

A．forgot to do                         B．forgot doing

C．have forgotten to do             D．had forgotten doing

6、 (2010年苏州一模)—Are you going to further your studies after graduation?

—Well，I________yet.I might make some other choices.

A．didn’t decide                 B．haven’t decided

C．don’t decide                 D．hadn’t decided

5、 (2011年海淀区第二学期期中练习)—Why didn’t you come to the cinema with us last Saturday?

—Oh，sorry.But I________the film.

A．see                                     B．saw

C．have seen                     D．had seen

4、 (2011年日照市调研考试)—Monitor?

—I’m not monitor of our class.I________with the teacher until the monitor is elected.

A．will just help                        B．am just to help

C．am just helping                     D．have just helped