1．【答案】B

2．【答案】C

3．【答案】D

4．【答案】A

5．【答案】B

6．【答案】D

7．【答案】C

8．【答案】B

9．【答案】C

10．【答案】B

11．【答案】D

12．【答案】C

13．【答案】C

14．【答案】D

15．【答案】C

16．【答案】C

17．【答案】B

18．【答案】A

19．【答案】B

20．【答案】C