桩号是指()。
A.测线上若干一定间隔距离的带有标志的点
B.指震源所处的位置
C.指采集站(检波器)接收地震波的位置
D.放置爆炸机并进行爆炸操作的地方
参考答案:A
—May I speak to Mary?
—Sorry, she isn't in. She _______ to Japan and will come back in two weeks. [ ]
A. has been
B. has gone
C. is going
正常情况下儿童乳牙出齐的年龄为()。
A.2岁
B.2岁3个月
C.2岁6个月
D.2岁9个月
E.3岁