--- How long ____ was this?

--- It’s been nearly six years now.

A．ago

B．before

C．later

D．partly

电视画面是从一定数量的画幅，以（）的连续运动中体现出来的。

A.每秒25帧

B.每秒30帧

C.每秒35帧

D.每秒40帧