局域网不提供( )服务。A．资源共享 B．设备共享 C．多媒体通信 D．分布式计算

某卫星运行1小时的行程约28 600 000m，用科学记数法可表示为

A．0.286×10⁸ m

B．2.86×10⁷ m

C．28.6×10⁶ m

D．2.86×10⁵ m

New technologies have made ____ possible to turn out new products faster and at a lower cost. [ ]

A. that            

B. this          

C. one            

D. it

_____time goes by, my grandfather’s memory seems to get worse and worse.

A．Though

B．As

C．Because

D．Since

运转设备的旋转部分清扫必须专人负责，定时清扫。

103型分配阀跳跃弹簧自由高为（）。

A.65.5～61.5mm

B.42.5～36.3mm

C.52.5～48.3mm

D.55.5～51.5mm