Yesterday I did my homework for two hours.
Yesterday I spent two hours for my homework.
(yesterday放前或后都没有关系)这上面的句子都是没有表明你两个小时有没有做完作业。只是说明你昨天有两个小时是在做作业。
如果你要表达你用两个小时做完了作业，可以是
Yesterday I spent two hours to finish the homework.(也可以用my homework，意思是我的作业；the homework也可以，指的是那个作业)
Yesterday the homework cost me two hours to finish.(这里的意思直译“昨天那个作业用了我两个小时来完成。”)
Yesterday I finished/did my homework in two hours.(这里“in”强调了你在两个小时内完成了作业)
追问谢谢你！👍🌹你的回答真详细。