It is not easy to finish all the homework=It is very difficult to finish all the homework.
意思是:要完成这么多家家庭作业很难
I didn’t leave until my father came back= I will leave after my father come back
意思是:等到我父亲回来我才能离开.It is not easy to finish all the homework=_________ _________ ________ __________ is not easyIt is not easy to finish all the homework=Finish all the homework is not easy