阅读下列短文，然后按短文后的要求完成所给出的题目。

根据短文内容完成句子。

1. If you are in space, you can see ________ sunrises and sunsets in a whole day.

2. Some astronauts think ________ is the most fun thing to do during their free time.

3. Astronauts have to attach their sleeping bag to the wall, or they will ________.

4. Astronauts often ________ during their free time.

5. 将文中划线的句子翻译成汉语。

某学校的保健老师在家长课堂讲课时，旁听的口腔专家指出下面哪一项说法容易引起误导

A．氟化物的使用可减少光滑面龋的发生

B．窝沟封闭可有效预防窝沟龋的发生

C．替牙期要特别注重第一恒磨牙的保护

D．10岁以前儿童需要家长帮助刷牙

E．刷牙可以有效预防窝沟龋和光滑面龋