考考你的记忆力，根据句意及首字母补全在本课中出现的单词。

1.We are d_____ from them.

2."R_____"means  "again".

3.Can you s_____ the song in English?

4.I hope you r_____ to tell him about it.

5.Do you have a s_____ friend?

6.I'm good at ping-pong. That makes me u_____.

7.Can you write a letter to me to d_____ yourself?

8.Let me i_____ my friend to you.

9.Do you know how they c_____ the festival?

10.We should be c_____ in ourselves.

2008年，张三大学毕业后，成立了一家专门从事楼房内外清洁的“保洁”公司。经营这样一家公司，你认为应关注哪些一般环境因素