下列物质中属于强电解质的是 A．NH3·H2O B．H2O C．CH3COOH

— Where was it ________ you met Mr. Brown for the first time?

— It was in the house ________ I was born.[ ]

A. where; that  

B. /; that

C. in which; where  

D. that; where

中国古代最早的纸币——“交子”出现在[ ]

A．秦汉

B．隋唐

C．宋代

D．元代

设（101）x＝（41）16，求x＝（）

A.6

B.10

C.8

D.12

制动缸密封式压形前盖变形或活塞杆孔偏磨一侧超过（）时更换。

A.1mm

B.2mm

C.3mm

D.4mm