“专治一身上下诸痛”的药物是（）。
A.川芎
B.郁金
C.延胡索
D.姜黄
E.乳香
参考答案：C
The art centre is _____ used to be a factory, _____ millions of tractors were made.
A．what; where
B．where; where
C．what; which
D．where; which
GPON系统采用WDM技术，实现何种方式的传输（）
A.单纤双向
B.单纤单向
C.双纤单向
D.双纤双向
