根据句意和单词首字母提示写单词。

1. Please t______ these new books to your classroom.

2.—Where's my cat? —It's on the f______.

3. Look! The soccer ball is u______ the chair.

4. Please put the table b______ the two chairs.

5. There are two doors i______ the wall.

电离室按工作方式分为（）和累积电离室。