一电量q₁=+1.0×10^-8C的点电荷，放在A点时所受电场力大小是2.0×10^-5N，将它从零电势O点处移到电场中A点时，需克服电场力做功2.0×10^-6J，选取无穷远处为零电势点，求：

（1）A点处的电场强度的大小．

（2）电势差U_AO．

（3）A点的电势为多少？

（4）q₁电荷在A点的电势能为多少？

Have you ever wondered ______ there are so many natural disasters across the world in 2010?

A．which it is that

B．what is it that

C．how it is that

D．why it is that