51.  Before the test of middle of the term, everyone tries harder to improve himself.

52.  Firstly, the economy in developing countries has been increased these years and the people's living standard has been highly improved.

53.  At last , the medical equipment is improved and medicine is enough to heal common diseases.

54.  It shows that the health gains in develop countries are improved very much.

55.  Secondly, with the development of developing countries, medical level is improved.

56.  In recently years, people in developing countries have done a lot to improve the people's healthy .

57.  The average age has improved about 20-year-old .

58.  First, the life's level of the developing countries' people has already improved.

59.  Latter , with the economy advancing and the society improving, people's life level is rising quictly .

60.  Firstly, living condition has improved in recent years.