小数的____添上“0”或者去掉“0”，小数的大小____，这叫做____。 

在相同的温度和压强下，相同体积的气体具有相同的分子数，反之亦然．取同温同压下相同体积的CO和O₂混合，在一定条件下充分反应，恢复到初始温度和压强．下列说法正确的是（   ）

1）感谢师恩；

2）你们之间最难忘的一件事；

3）希望下学期还当她的学生。

注意：1）词数100左右；

2）可以适当增加细节，以使行文连贯；

3）开头语及结尾已为你写好，不计入词数。

Dear Grace,

Yours Sincerely,

Li Hua

根据短文理解，从A、B、C、D四个选项中选择最佳答案。

    Almost everyone knows about Olympic Games. But not 1 people know how they started, why they once stopped and when the People's Republic of China took part in the Olympics.

    People 2 the first Olympic Games in Greece (希 腊）in 776 B. C. They had the Olympics 3 four years in summer. The first Olympics 4 for only one day and there was only one contest (比赛).It was a short race. Only Greek men could 5 in the race. Women couldn't 6 the race.

    When Rome (罗马）ruled Greece, the Olympics 7.

    The People's Republic of China took part in the Olympics 8 the first time in 1952. 9 China got no gold medals until (直到）1984 in the Los Angeles Olympics. China won the first 10 in the 29th Beijing Olympics in 2008. We hope China will get more gold medals in the 30th Olympics in London. Come on, the Chinese players!