51.【答案】D。12
52.【答案】A。37
53.【答案】C。6500
54.【答案】D。4
55.【答案】C。55
56.【答案】B。6050
57.【答案】B。8
58.【答案】A。1/2
59.【答案】C。6
60.【答案】B。10
61.【答案】C。8%
62.【答案】D。6
63.【答案】D。9
64.【答案】D。34
65.【答案】D。15
