在等差数列{a_n}中，a₄=9，a₉=-6，S_n是其前n项和，以下命题正确的是______

①S₆=S₇；②{a_n}是递减数列；③S₇=S₈；④S₅=S₇．

根据句意及首字母或汉语提示，将单词的正确形式写在相应的横线上。 .

1. Look! The children _____________(swim) at the pool.

2. — What's she doing?   

    — She ___________ (not do) her homework. She's reading.

3. — What are the boys doing?   

    — They are t___________ about the pictures.

4. — How's the w___________ in Beijing?

    — It's raining.

5. It'll be ___________(sun) in Harbin tomorrow.

6. It's very c___________ outside. Please put on your coat when you go out.

7. W___________ is from November to January in China.   

8. The Greens want to go to Hawaii on v___________.

9. Some people are t___________ photos in the park . 

10. We are very ___________ (surprise) at the news.