根据下面各题括号里汉语的提示和句子的意思，写出恰当形式的英语单词，每空格只写一个单词。

1. Today is Tree Planting Day. The students are ______________ (挖) holes for trees.

2. The shopping-mall is on ______________ (营业) from 9:00 a.m. to 10:00 p.m.

3. He is still sad though his pet dog has been ______________ (死的) for five years.

4. It is hard to ______________ (选择) between staying with my parents and going abroad.

5. The temperature in Harbin is very low in winter, usually below ______________ (零).

6. The man seemed to be waiting for ______________ (某人) in the building.

7. I heard some noise from the room ______________ (在上面).

8. What a lovely morning! The ______________ (鸟儿) are singing in the trees.

9. Would you please ______________ (邮寄) this letter for me on your way home?