"Eyes are windows of the soul." Everyone knows the 1  of the eyes.   2  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 3  protect your eyesight(视力).
You should not keep your eyes 4  for a long time. When reading, you should keep the books about a foot away from you. After reading for an hour 5  two, you 'd better have a   6  by looking into the distance(远处).
You must remember not to read in dark light or in   7 , not to read on a moving bus or in bed. Doing eye exercises will help   8  to protect your eyesight.
In a   9 , to keep   10  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