—Where ______ they from?
—They're from China.[ ]
A. is
B. am
C. are
C
贵重中药临床用量一般是（）
A.0.03～0.6g
B.0.3～1g
C.1～3g
D.3～6g
E.6～9g
电梯处于什么状态时，最远反方向载车信号无效？
