根据句意及汉语提示完成单词。

1. This suit is out of style, _______ (然而) , I like it very much and often wear it.

2. We're doing something to make our city clean, so there will be less _______ (污染) in the future.

3. My grandfather lives _______ (孤独地), because my parents are so busy that they don't often go

    home to see him.

4. It is _______ (不可能的) to learn English well in a day.

5. I don't think l will _______ (失败) in the math test. I can pass it.