6.  The earth is a rocky planet where there is liquid water, which is necessary for life to e___________ .

5.  It is possible to_____ _ (繁殖)these bacteria in the laboratory.

4.  Fruit juice can be______ (有害的)to children's teeth.

3.  It is obvious that the existing exam_______ (制度)can no longer perfectly show the students' abilities.

2.  This scientist has put forth a new______ (理论)in his research field.

单词拼写

1.  The black cloud promises a________ (猛烈的）storm.

15.  Shanghai is the first city in the world     a high-speed maglev train, from the city to Pudong Airport.

A. building     B.  having built

C. to have built   D. built

14. It is difficult for children to change their eating habits later in life.  ， parents should encourage healthy eating from an early age.

A. Otherwise  B. Therefore

C. Besides    D. However

13. I know that it will be difficult to pick him out in such a crowd  but if you    happen to see him, give him this packet.

A. would     B. might

C. should   D. could

12. Everybody has     responsibility to save water ， if future  generations   are to enjoy    similar standard of living to the one we enjoy now.

A. the; /       B.  a; a

C.  /； the    D.  a; the