激光发射出一束狭窄的光线。

A laser emits a narrow ___beam of light.

我开始感到不耐烦时，一扇门打开了，让一束光线照进黑暗的房间。

I was beginning to feel rather impatient when a door opened letting a ___beam of light come into the dark room.

手电筒在黑暗中产生了一道明亮的光束。

The flashlight produced a bright ___beam in the darkness.