并联电容器主要作用是（）改善电压质量。

A、补偿无功功率，提高功率因数

B、提高供电设备的出力

C、降低功率损耗和电能损失

D、减少电费

--What do you think of Harry, our new classmate?

--I am not sure, but he is always asking ______ questions.

A．a great many of

B．a great many

C．a great number

D．a great amount of