1．【答案】B

2．【答案】C

3．【答案】B

4．【答案】D

5．【答案】C

6．【答案】D

7．【答案】D

8．【答案】B

9．【答案】B

10．【答案】C

11．【答案】D

12．【答案】A

13．【答案】B

14．【答案】C

15．【答案】B

16．【答案】D

17．【答案】A

18．【答案】A

19．【答案】A

20．【答案】D