"Eyes are windows of the soul." Everyone knows the 36 of the eyes.  37 more and more students are becoming near-sighted(近视). So how to protect the eyes is still a serious problem. Here is some advice on 38 protect your eyesight(视力).
You should not keep your eyes 39 for a long time. When reading, you should keep the books about a foot away from you. After reading for an hour 40 two, you 'd better have a 41 by looking into the distance(远处).
You must remember not to read in dark light or in 42, not to read on a moving bus or in bed. Doing eye exercises will help 43 to protect your eyesight.
In a 44 , to keep 45 eyesight, we must have good studying habits.

A.importance	B. experience	C. difference
A. So	B. Because	C. But
A. what to	B. how to	C. when to
A. working	B. walking	C. waking
A. and	B. or	C. as
A. talk	B. rest	C. by
A. the earth	B. the star	C. the sun
A. him	B. us	C. you
A. word	B. sentence	C. letter
A. bad	B. good	C. weak