已婚女子，末次月经不详，宫腔探及胎儿回声，头臀长2cm，计算孕龄是（）
A.4～5周
B.6周
C.8.5周
D.10.5周
E.7周
参考答案：C
The police were seeking more information to find out _____ the rich merchant.[ ]
A. who was it that killed
B. who it was that killed
C. it was who killed
D. who was it killed
为什么离心泵在出口阀关闭后再停车？
