choose the correct word:
17.can/should I ask you a question?
18.will/shall we go out for lunch today?
19.you must/shouldn't stay at home if you are all.
20.tommy can't/couldn't tell the time when he was a baby.
21.my book can't/mustn't be in the house.I've looked everything.
22.you haven't/needn't clean the windows.I've already done them.
23.sam left late for the airport this morning.He should/could have missed his flight​