Last month she explained to one of her classes about sound,and she decided to test them to see how successful she had be

问题描述:

Last month she explained to one of her classes about sound,and she decided to test them to see how successful she had been in her explanation.这句话啥意思?

上个月,她向她的其中一个班讲解了什么是声音,然后她决定去考考他们,来看看自己在讲解声音这件事上有多成功.