1．【答案】D

2．【答案】B

3．【答案】A

4．【答案】C

5．【答案】D

6．【答案】B

7．【答案】C

8．【答案】A

9．【答案】D

10．【答案】D

11．【答案】C

12．【答案】C

13．【答案】D

14．【答案】C

15．【答案】B

16．【答案】B

17．【答案】A

18．【答案】A

19．【答案】A

20．【答案】B