山药可用于治疗
A．气虚欲脱，脉微欲绝B．中气下陷之久泻脱肛，脏器脱垂C．肾虚遗精，尿频D．调和诸药E．血虚脏躁
参考答案：C
I don't think the situation has reached the point ______we have to give up. [ ]
A. which
B. where
C. when
D. as
英美学派、法瑞学派、北欧学派和苏联学派是在生态学的______时期产生的。
