根据句意和首字母提示完成单词。

1. He often plays football a______ school.

2. I think it's h______ past eight now.

3. M______ is the second day of a week.

4. I'm b______. I have no time to go to the park with you now.

5. S______ 10th is Teachers' Day.

如图所示，有一混合正离子束先后通过正交电场、磁场区域I和匀强磁场区域Ⅱ，如果这束正离子束在区域I中不偏转，进入区域Ⅱ后偏转半径又相同，则说明这些正离子具有相同的

A．速度

B．质量

C．电荷量

D．荷质比