根据所给汉语将下列句子补充完整。

1．人们初次见面时应该握手。

People are ________ ________ ________ ________ when they meet for the first time.

15. The dog __________(train) to understand different instructions for two years.

14. We got a _________ (science) result through lots of experiments.

13. Who can tell me the _____________ (long) of the Yellow River?

12. It’s _______________(polite) to cut in line.

11. It is rainy today, but tomorrow we’ll have 　　　　　(please)weather.

10. Alter the earthquake most people in the village lost their lives, only a few s　　　　 .

C) 根据句意，用所给单词的适当形式填空。

9. The thick smoke from the factory had a bad i　　　 on the environment around.

8. When I got home, mother was busy cooking in the k　　　　 .

7. There are few new words in the passage, we can read ii e　　　　 .