火警探测器按探测范围可分为两种：（）.
A.串联型和并联型
B.电阻型和电容型
C.温度型和烟雾型
D.单元型和连续型
参考答案：D
Yantai is a beautiful city with many places of interest. ________tourists come here every year． [ ]
A. Thousand of
B. Thousand
C. Thousands
D. housands of
黄芪与茯苓属于的配伍关系是
A．相须B．相使C．相杀D．相恶E．相反
