孕8～9周时，胎盘的外形常呈（）
A.半月形
B.长圆形
C.扁圆形
D.细长条形
E.菱形
参考答案：A
乙数是210，甲数是乙数的4倍，甲数是______．
23. There were reports that three companies were ______ to market drug.
A．advocating
B．previewing
C．negotiating
D．Reserving
