单项选择。
He comes here ____ bike. [ ]
A. by his
B. take his
C. on his
D. in his
答案:C
下列可称为导弹的是()
A.人造卫星的火箭
B.制导炸弹
C.制导鱼雷
D.火箭助飞的鱼雷
根据《水准仪检定规程》(JJG425—2003)规定:水准仪检定周期为()。
A.3个月
B.6个月
C.1年
D.2年