问两道语法

The photoperiodic response of algae actually depends on the duration of darkness, ___.

A)the light is not on

B)and not on light

C)but is not on the light

D)in not on light

答案选Ｂ，没有疑问．但是我想问如果是but　not　on　light是不是更好呢？这种说法对不对？

The lenses in an optical microscope bend the light passing through a specimen to form an image of that specimen that is much larger ___ actually viewed.

A)than it

B)than the one

C)one than

D)than one which

答案Ｂ，想问Ａ为什么错？

1 but not on light is also right.

2 定语从句的省略

　A　不行, 注意比较的对像。是Image.