When I was six years old I visited the Great Wall ,为什么when后面加过去式

问题描述:

When I was six years old I visited the Great Wall ,为什么when后面加过去式

当我还是六岁的时候,我去了长城.这是对过去事情的叙述,所以用过去式.不是因为when而用过去时态,要理解句子意思.