什么是客流的抽样调查？
参考答案：
从调查对象中抽取部分或个体进行调查，然后分析、推算全部调查单位有关数据和情况。
-Did you come to the museum by bike yesterday?
-No. Two inches of snow fell during the night. As a result, several main roads___
A．piled snow
B．had been closed
C．were blocked
D．covered with snow
脑血栓形成在急性期的治疗方法可选用（）.
A.早期溶栓治疗
B.静滴PAMBA
C.静滴低分子右旋糖酐
D.静滴甘露醇
E.口服去痛片
