21
[答案]:B
[解析]:参见教材P295
22
[答案]:D
[解析]:参见教材P296
23
[答案]:B
[解析]:参见教材P299
24
[答案]:B
[解析]:参见教材P300
25
[答案]:D
[解析]:参见教材P300
26
[答案]:D
[解析]:参见教材P300
27
[答案]:B
[解析]:参见教材P303
28
[答案]:C
[解析]:参见教材P301
29
[答案]:C
[解析]:参见教材P301
30
[答案]:C
[解析]:参见教材P302
31
[答案]:A
[解析]:参见教材P302
32
[答案]:C
[解析]:参见教材P303
33
[答案]:D
[解析]:参见教材P304
34
[答案]:A
[解析]:参见教材P304
35
[答案]:B
[解析]:参见教材P305
36
[答案]:A
[解析]:参见教材P299
37
[答案]:B
[解析]:参见教材P305
38
[答案]:A
[解析]:参见教材P308-309
39
[答案]:D
[解析]:参见教材P308
40
[答案]:C
[解析]:参见教材P309
41
[答案]:C
[解析]:参见教材P310
42
[答案]:D
[解析]:参见教材P310
43
[答案]:B
[解析]:参见教材P312
44
[答案]:C
[解析]:参见教材P312