如图甲、乙所示为定性研究平行板电容器的电容与其结构之间的关系的装置，平行板电容器的A板与静电计相连，B板和静电计金属壳都接地，若充电后保证电容器带电量不变，试指出如图所示的情况下，静电计指针的偏转角度变化情况．

（1）正对面积减小时，静电计指针的偏转角度______．（填“变大”“变小”或“不变”）

（2）板间距离增大时，两板间的电场强度______．（填“变大”“变小”或“不变”）

I'm not sure whether he has finished writing the book, but he ____ it last month. [ ]

A. worked at

B. was working on

C. worked on

D. was working at