He when to school when he was nine years old.为什么时态一致?

问题描述:

He when to school when he was nine years old.为什么时态一致?

译:他在九岁时上学(若when是went的话)
在过去某时做某事,均用一般过去时,当然应该一致啊

意思是:他在9岁时上学了.他9岁时已经过去,所以前面的动词用过去式.