【参考答案】
1.C2.D3.E4.B5.C6.D7.B8.B9.E10.C
11.B12.A13. D14.B15.B16.D17.C18.C19.B
20.D 21.E22.B23.B24.E25.D26.C27.B28.D
29.C30.C31.A32.E33.D34.C35.D36.B37.D
38.B39.B40.B 41.E42.A43.C44.C45.B46.C
47.A 48.C
