抛石挤淤时，不正确的是（）。
A.片石不宜小于30cm
B.自中线向两侧展开
C.自两侧向中线展开
D.自低向高展开
参考答案：C, D
I failed in the final examination last term and only then ________ the importance of studies.
A．I realized
B．I had realized
C．had I realized
D．did I realize
闭经的治疗原则是
A．益气养血，调理冲任
B．补益肝肾，调理冲任
C．祛痰除湿，调理冲任
D．滋阴养血，调理冲任
E．虚者补而通之，实者泻而通之
