低速暖机时，若真空太高，暖机时间会（）
A.缩短
B.不变
C.加长
D.不一定
参考答案：C
This is an unpleasant subject_ ____ we might argue for a long while. [ ]
A. in which
B with them
C. about which
D with it
含濒危野生动植物成分的药品
