You ( can / can't ) park here! It's private parking. You ( can / can't ) park at the public parking on Main Street.
You can't park here! It's private parking. You can park at the public parking on Main Street.
My Mom is very busy because she ( has to / doesn't have to ) work full time.
My Mom is very busy because she has to work full time.
I ( can / can't ) unlock the door, because I don't have the keys!
I can't unlock the door, because I don't have the keys!
Does your sister have to take out the rubbish?
No, she doesn't.
