题目内容：

阅读短文，根据短文内容，从短文后的五个选项中选出能填入空白处的最佳选项。每个选项只能用一次。

  Every four years, people will look forward to the biggest sport game, the Olympic Games. 

  1. Rio 2016 organizers have revealed（揭露） the medals that will be competed for at this summer's Olympics. A total of 2,488 medals, each weighing 500g, have been produced - with 812 gold medals, 812 silver medals and 864 bronze medals. They were made with "sustainability（可持续性） at their heart", say organizers. 2. ,the silver medals and bronze medals are made from 30% recycled materials, and half of the plastic in their ribbons is from recycled plastic bottles.

     3. , more problems of this big project have been revealed. It is known to all that a city will be given the right to hold the Olympic Games at least 8 years ahead, so that the government will have enough time to prepare. But the biggest problem is still the unfinished buildings.  4..Rio is not the developed city, its health care can’t compare with the developed countries. As its hot weather and other reason, some diseases are easily to spread. It has been reported that some athletes have dropped out of this coming event, for there exists a kind of virus（病毒） which will make people sick badly.

5.  , we have to admit（承认） that it is still a successful Olympic Games.

A. The second problem is the health. B. This year, The Rio held the 31th Olympic Games. C. The gold medals are free from mercury（汞） D. Though facing so many problems E. As the media much pay attention to report the progress