6. As there is less and less coal and oil, scientists are exploring new ways of making use of    energy, such as sunlight, wind and water for power and fuel.

A. primary         B. alternative          C. instant         D. unique

    —Have you __________ ?

—No. I had the wrong number.

A. got in        B. got away      C. got off       D. got through

 I’d like to arrive 20 minutes early___ I can have time for a cup of tea.

A. as soon as   B. as a result   C. in case  D. so that

–What do you think of teaching, Bob?

–I find it fun and challenging. It is a job ___ you are doing something serious but interesting.

A. where         B. Which    C. When     D. that

Although ______ for many years, the two old sisters recognized each other at once.

A. having been separated                   B. being separated

C. having separated                        D. had been separated

—I hear you've got a set of valuable Australian coins. ___I have a look？

—Yes, certainly.

A．Do  B. May  C. Shall    D. Should

They use computers to keep the traffic _______ smoothly. 

A. being run       B. run         C. to run        D. running

Look at the trouble I’m in! if only I ____your advice.

A.     followed  B. . would follow  C.  had followed  D.  should follow

The children all turned ____ the famous actress as she entered the classroom.

A. looked at                  B. to look at

C. to looking at               D. look at

What is most obvious in this book are all those details of daily living which make Mrs. Richard _____ common.

A. nothing but      B. anything but     C. above all     D. rather than