根据短文内容， 从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。
You may know the benefits of laughter on the mind and spirit. _1___ Norman Cousins used to say that laughter has such a good effect on your body that it is like “inner jogging”.
Mayo Clinic Health Letter reports that laughter aids breathing by incresing your breathing rate.. It can even help clear mucus(黏液) from your lungs.
__2__ It increases circulation(循环) and improves the flow of oxgen and nutrition to tissues(血管) throught your body..It can help protect you against a heart attack.
__3___ It helps fight off colds, flu,etc. by increasing the concentration of immunolobulin (免疫球蛋白A) in your saliva(唾液) .And it may help control pain by raising the levels of certain brain chemicals.
In addition, it is a natural stress reliever（缓解）.Have you ever laughed so hard that you bent over, fell off your chair, or spit out your food? __4___
I read that a child laughs 400 times a day on average, while an adult laughs only 15 times each day. The good news is that you are allowed more than 15 laughs a day! Go ahead and double it and make it 30 times today. You may begin to notice immediate improvement in your relationships! Then double it again! __5___ People will enjoy being around you as well.
Laughter: it’s the best medicine!
A. Laughter is also good for your heart.
B. Laughter can bring some relief from mental stress.
C. A good, hearty laugh relieves physical tension(紧张) and stress.
D. However, it is confusing why laughter makes people feel so good.
E. A good laugh helps build up your body to protect against diseases
F. You are likely to feel even better and deal with problems more effectively.
G.  However, are you aware of how much a good laugh can help you physically?