1.---You could have asked your teacher for help .H

问题补充：

1.---You could have asked your teacher for help .He is kind-hearted .---Yes,a whole day

答案：

这是一般过去时的现在完成时,原意是,你应该向你的老师求助.他很好心.

而第二句的主语是天,意思是如果不求助这一天就会被浪费掉,所以用被动语态.A