A project in Tanzania and Mozambique is teaching rats how to save human lives. 1 a sharp sense of smell， giant African pouched rats(非洲囊鼠) are being trained to 2 land mines(地雷) left by the countries’ civil wars.

The Dutch organization APOPO is carrying out the 3 project. Training begins when the 4 are 4 weeks old. Scientists let the baby rats get 5 ， with humans so they won’t be afraid of people and 6 surroundings. After that， they teach the rats to link a click sound with food.

7 the rats have learned that， scientists then train them to 8 the difference between the smell of TNT and other smells. Then the 9 ， is sounded and they are given a bit of banana.

10 all， it takes nine months of on and off field training for a rat to be able to 11 the job.

“The training is not easy，” said trainer Abdullah Mchomvu. “You have to be 12 . Sometimes I get angry， but then again 13 tell myself these are animals.”

14 the trainer also believes that “this work saves lives”.

When fully trained， the rats 15 out a mine， then sit and scratch the ground until they are given food. A human landmine expert then destroys the mine. It 16 two detainers(掃雷人員) a day to clear a 200 square meters minefield， but 17 they work with two rats they can sweep it in two hours.

“Detection is the most difficult， 18 and expensive part of mine action. Since rats are much easier to train than dogs， they are more 19 for the work. So far they have helped re-open almost 2 million square meters of land，” said Bart Weetjens， the founder of APOPO.

The rats are about 75 centimeters long and weigh about 1.35 kilograms. This means they can run across a minefield without setting off the mines. 20 ， no animals have been lost to any errors， and they are called “hero rats” for the great work they perform.

1. A. Without B. With

C. Despite D. Besides

2. A. find B. destroy

C. store D. bury

3. A. military B. training

C. research D. scientific

4. A. soldiers B. children

C. rats D. dogs

5. A. afraid B. familiar

C. angry D. tired

6. A. new B. war

C. terrible D. foreign

7. A. Unless B. Until

C. Once D. Before

8. A. know B. tell

C. find D. see

9. A. whistle B. mine

C. clock D. click

10. A. At B. Above

C. After D. In

11. A. take in B. take up

C. take on D. take over

12. A. cautious B. patient

C. calm D. silent

13. A. I B. you

C. they D. it

14. A. But B. And

C. Or D. For

15. A. figure B. point

C. smell D. speak

16. A. needs B. costs

C. has D. takes

17. A. Since B. After

C. unless D. if

18. A. famous B. natural

C. dangerous D. important

19. A. suitable B. careful

C. sincere D. anxious

20. A. If so B. By far

C. As far D. So far