轮式挖掘机转子式液压转向机构是由（）组成。
A.液压泵
B.转向器
C.转向液压缸
D.转向轮
E.转向臂
参考答案：A, B, C, E
下述支气管扩张的影像特点，错误的是（）
A.局部肺纹理增多
B.环状或蜂窝状影
C.斑片状、索条样影
D.可有葡萄、手套征
E.普通CT扫描正常可排除本病
I didn't think maths ______ important at that time. [ ]
A. is
B. were
C. are
D. was
