51.  And the second reason is it can train our determination when we take a long swimming.

52.  But, now people in the world much care of their healths , and they believe science, that is also a reason .

53.  The reasons of structure changing much of their health lie in many aspects.

54.  The mainly reason is that science technology is developing very fast.

55.  the reason May be here.

56.  They also relize that so many other reasons inflect their health , they deal with them .

57.  Reasons are many .

58.  There are also other reasons in it .

59.  There are many reasons to this alternaty .

60.  The basic reason, I think, is the developing of industry.