I ...........go to work tomorrow because it is Memorial Day. should shouldn't don't have to. We .........go now.It's getting dark. should can mustn't. Yesterday, I ...........study all day for my French final. I didn't get to sleep until after midnight. musted had to shouldn't. You ............forget to pay the rent tomorrow. The landlord is very strict about paying on time. must don't have to mustn't. What do you think I......... do? must should would. .........you help me, please? can should must. ..........I help him? What do you think? Shall Must Have I. Ted's flight from Amsterdam took more than 11 hours. He ..... be exhausted after such a long flight. mustn't must should. Susan ...........hear the speaker because the crowd was cheering so loudly. mustn't couldn't can't. You ............worry so much. It doesn't do you any good. must mustn't shouldn't. You.......... take along some cash. The restaurant may not accept credit cards. should mustn't could. He .........speak French when he was five. He was a very clever child. can must could.