---How much difficulty did you have________________ this problem? ---_____________. It's quite easy.
Do you come here ____your car?
---_____must I take this medicine every day? --- Three times a day.
Have you ever _________ an athlete named Beckham ?
I don’t know if my uncle _______ . If he _______ , I will be very happy .
—Will you go shopping tonight ? --If you go , ________.