（6）处填入（）。

A.over
B.around
C.off

If you are writing or studying, it makes very much difference where the light comes from. People who use books and pens every day (1) to be especially careful about the direction from which the light shines on their work.A house gets it’s light (2) from daylight through windows (3) is very good to use or from the lamps, but no matter what kind of light it is, the direction it slants(倾斜) towards our books or our work is a matter of great (4) to the eyes.

Take a book,stand with your back toward the window, and try to read. Your shadow falls across the page and makes it bad for your eyes as if you were in a (5) room.

Now turn (4) and face the window. The page is the shadow again,while the bright light is in your (7) . Try standing with your right side towards the window. This is very good for reading, (8) if you were writing,the shadow would (9) the page and trouble you a little.

There is just one other way: stand with your (10) side to the window. Now everything is perfect for reading and for writing, too.