The children went home from the grammar schoo1,their lessons  ________ for the day．

A．finishing

B．finished

C．had finished

D．were finished

有的同学想检查一下自己所用的台灯在发光的同时是否会发出大量的紫外线，而伤害自己的身体，可以采用什么方法进行检查？