昨晚你花了多长时间做作业？用英语怎么说

How long did you spend (in) doing your homework last night?
spend sometime (in) doing sth (表达花时间做某事时，in可以省略）
spend sometime on sth (花时间在某事上用on)
这句话还可以说成How long did it take you to finish/do your homework last night?
这里要注意的语法点是几个花时间做某事和花时间在某事上的短语的用法
如，spend, it takes sb sometime to do sth。
希望对楼主有所帮助

Last night, how long have you been doing your homework?
我在外国留过学的！！
望采纳！

How long did you spend ON doing homework AT last night

How long did you spend on your homework last night?

How much time do you spend finishing your homework