单项选择题
A.二级 B.三级 C.四级 D.五级
A.一级 B.二级 C.三级 D.四级
A.17 B.20 C.18 D.19
A.17 B.18 C.19 D.20
A.11% B.12% C.13% D.65%
A.1 B.2 C.5 D.9
A.27 B.28 C.29 D.30