如图所示，E="10" V，r="1" Ω，R1=R3="5" Ω，R2="4"

       We all know that it is  1   to keep healthy. But not all people know  2   to keep healthy. After
five days' hard work, we need to have a good rest at weekends. But it seems that some don't know
how to spend weekends in the right way. They enjoy   3   cards at night and don't go to bed until
midnight or even later. Some gamble (赌博) all night. They forget that to get   4   sleep is essential
(必要的) for health. Some never get up early in the  5   and take some exercise. It is true that doing
exercise is very important for us to keep   6  . Some smoke a lot. They forget that   7  smokers are
more likely (可能) to have lung cancer (肺癌) than those who don't smoke. Some drink too much
wine.  8  too much is harmful (有害) to the body. Some eat too much rich food and get fatter and
fatter. If you are much too fat, you may always   9   tired. Vegetables are good to the body. But some
don't like eating vegetables.   10  is also very good to body. As a saying (谚语) goes, "An apple every
day keeps the doctor away." So don't forget to eat some fruit.