若尿HCG＜2500U并逐渐下降，则可能的情况是（）
A.睾丸畸胎瘤
B.宫外孕
C.死胎
D.葡萄胎
E.绒毛膜癌
参考答案：C
—John has spoken Japanese well now. —______, and _____.
A．So he has , so you have
B．So he has , so have you
C．So has he, so have you
D．So has he, so you have.
混凝土立方体标准抗压强度标准值，试验时要求的养护时间为（）天。
A．3
B．7
C．28
D．45
