--Where were you at 7:00 last night?

-- I         to my mom at home.

A．write

B．was writing

C．wrote

D．am writing

测距机编码的脉冲间隔是指（）的间隔。

A.相邻两次询问或探测脉冲之间

B.询问或探测脉冲的脉冲重复周期

C.相邻编码脉冲组之间

D.编码脉冲组两个脉冲之间