She must work to earn money to feed children. MOM needs hard work to earn money to send the study because she thinks he wants to keep the ball high, so the future ahead will be difficult.
She had to work to earn money to feed her children. She had to work hard to raise money to send their children to school because parents want their children to think that high school to the future, it is not difficult.
I have to make money to feed you. I have to work hard to earn money to send their children to school, because I think I want you to learn the opponents to the future is not hard.