题目内容：

B

Exercise is good for you, but most people really know very little about __36___ to exercise properly. So when you try, you _   37  __ run into trouble.

Many people believe that when specific muscles are exercised, the fat in the neighbouring area is “burned up”. Yet the truth is      38 ___ exercise burns fat from all over the body.

Studies show muscles which are not exercised lose their strength very quickly. To regain it __   39    (need) 48-72 hours and exercise every other day will keep a normal level of physical strength.

To lose weight you should always “work up a good sweat” when __ 40    _ (exercise). Sweating only reduces body temperature to prevent heating. This is nothing _  41 __ water loss.

Walking is the best and easy-to-do exercise. _  42   helps the circulation of blood throughout the body, and has a direct effect _   43   _ your overall feeling of health. Experience says that 20 minutes’ exercise _  44   __ day is minimum amount. But if your breathing doesn’t return to normal state within minutes ___  45    you finish exercising, you’ve done too much.