the boy spent as much time watching TV as he did studying这边studying前为什么要用did,

问题描述:

the boy spent as much time watching TV as he did studying
这边studying前为什么要用did,

did代替前面的spent ,为了避免重复,用助动词替换

did指代前面的动词spent.为了避免重复,用did(用过去时did,是因为spent是过去时)

did 是指代 spent 这个单词的哦.
因为这里比较的是不是两个东西:watching tv 和study 而是 这个男孩spend 多少时间在这两个里面,对比的是spend的时间哦,所以要用did 来指代spend
祝好.