下列有关分子的知识，正确的是（）

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根据短文内容，完成下列各题。

    In China, September 10th is a special day. It's Teachers' Day. Teachers' Day began in 1985. It is a great day for all the teachers and also a happy time for us students. How do we spend Teachers’ Day every year?

    On that day, we go to school early in the morning, and put a bunch (束) of flowers on our teacher's desk to give him or her a big surprise. Some of us help him or her to do some easy work. And others stand at the school gate to say hello to teachers when they go into the school.

    In the afternoon, we have a party. We sing and dance with the teachers.

    All of us are very happy. The teachers say that the best reward (奖励，奖赏) for them is to see our great progress(进步).

“人贵有自知之明”告诉我们（   ）