how long does she do homework
问题描述:
how long does she do homework
答
how long 一般与现在完成式连用,
也可用于一般式.
how long can you stay?
how long has she done homework?
在这里表达的意思是说她做作业用了多长时间?语意指的是过去的动作,所以选用这个时态恰当些.