XDF-ex2-25

woodruff1

The van de Graaff generator, an electrostatic machine used of nuclear physics to study transformations in subatomic particles, produces powerful electric currents.

of 改为什么?

dhhgh11

把OF 改为FOR 或者是OR吧，BE USED TO ；BE USEED FOR/IN是固定搭配。

woodruff1

thanks   a     lot  !!!!!!!!!!!!!!![em24]