根据句意及汉语提示填空

1. Smoking is bad for our lungs. It may cause _______ (癌症).

2. I want to _______ (选择) a nice gift for her as a birthday present.

3. The burglar (盗贼) got in_______ (从，通过) the window.

4. Li Fei likes throwing _______ (垃圾) about. That's not polite.

5. Look! She is _______ (扫) the room now.