Bears and humans often meet in National Parks. Although campers and hikers are warned not to 1 the bears， many people ignore these 2 and feed the bears anyway. When bears are used to peoples 3 ， problems soon arise. Bears like to eat a large variety of things， both meat and vegetables. 4 human assistance， bears live well on roots， twigs， leaves of trees， insects and small animals. With 5 around， the bears tastes quickly 6 to include sandwiches， hot dogs， hamburgers， and anything else they can get from humans.

Bears often 7 clever strategies （策略） for getting people to let go their food supplies. More often than not， an 8 hiker has taken off his or her pack for a rest only to have a 9 charge out of the woods， 10 the pack and quickly disappear into the underbrush with it. Hanging the pack on the tree branch wont 11 .

Bears have been known to climb up， jump off， and catch the pack on the way 12 . One mother bear stretched up with her baby on her shoulders to 13 a pack stored on a pole. Many bears threaten people into 14 their supplies. Although a bear is 15 to attack a person and would probably run away if 16 at， few people are willing to do so. Most people drop the pack and run the other way. This， of course， 17 the bear. In some places， the Park Service installed （安裝） some metal barrels with lids to help campers keep their 18 safe from bears. Although the bears were unable to 19 these containers， the effort was less than successful. Most campers， unable to 20 the metal drums from rubbish cans， never used them for the intended purpose.

1. A. hurt B. feed C. hunt D. frighten

2. A. dangers B. ideas C. problems D. warnings

3. A. food B. behavior C. life D. habit

4. A. Besides B. Except C. For D. Without

5. A. people B. vegetables C. meat D. food

6. A. turn B. expand C. lose D. limit

7. A. understand B. need C. study D. develop

8. A. unfriendly B. unsuspecting C. unkind D. unfortunate

9. A. monkey B. child C. bear D. thief

10. A. seize B. find C. steal D. damage

11. A. help B. disappear C. exist D. matter

12. A. away B. off C. down D. up

13. A. control B. reach C. carry D. discover

14. A. sending out B. taking out C. giving up D. picking up

15. A. possible B. ready C. unlikely D. nervous

16. A. looked B. screamed C. laughed D. aimed

17. A. delights B. interests C. warns D. comforts

18. A. goods B. products C. supplies D. lives

19. A. understand B. see C. find D. open

20. A. keep B. tell C. differ D. separate