[解析]:参见教材P253
40
[答案]:A
[解析]:参见教材P248
41
[答案]:A
[解析]:参见教材P248
42
[答案]:A
[解析]:参见教材P253
43
[答案]:A
[解析]:参见教材P253
44
[答案]:C
[解析]:参见教材P254
45
[答案]:A
[解析]:参见教材P255
46
[答案]:B
[解析]:参见教材P255
47
[答案]:D
[解析]:参见教材P256
48
[答案]:D
[解析]:参见教材P256
49
[答案]:C
[解析]:参见教材P260