However, brain thinks that the reflected light comes to eyes in a straight line, so an image is seen behind the mirror just on the extending line of the reflected light.

而大脑则以为反射光线是沿直线到达眼睛的，因此沿反射光线向后延伸，从而在镜子后面看到一个影像。

youdao

He said the South would accept nothing less than extending the Missouri compromise line west to the Pacific Ocean.

VOA: special.2009.03.19

The campaign group said jobs, business and improved contacts between academic centres would benefit by extending the line.

BBC: Rail link 'should extend to Cambridge'

Jobs, business and improved contacts between academic centres would benefit by extending the line to Cambridge, Railfuture said.

BBC: Rail link 'should extend to Cambridge'

Elsewhere, regulators have chosen to allocate the funds to extending fixed-line networks, rather than cheaper mobile networks.

ECONOMIST: Telecoms in the developing world