词形变换 根据句意，用括号中所给单词的正确形式填空，每空一词。

1. There will be more 　 　（tree） in the northwest of China.

2. High﹣speed trains are much 　 　（fast）than traditional ones.

3. Turn right at the second 　 　（cross） and the hotel is on your left.

4. Mr.Green 　 　（work） in our school ten years ago.

5. It is 　 　（harm） to the environment to kill the wild animals.