1．【答案】B

2．【答案】A

3．【答案】A

4．【答案】A

5．【答案】C

6．【答案】C

7．【答案】B

8．【答案】D

9．【答案】D

10．【答案】C

11．【答案】D

12．【答案】B

13．【答案】B

14．【答案】D

15．【答案】C

16．【答案】B

17．【答案】D

18．【答案】C

19．【答案】B

20．【答案】C