I’m feeling much better now, so you           call the doctor.

—Tom graduated from college at a very young age.—Oh,he__________have been a very smart boy then.

Charlie ______ be really difficult at times even though he’s a nice person in general.

—Can I go to the park, Mum?—Certainly. But you ______ be back by six o’clock. 

It has been announced that all the candidates______ remain in their seats until all the papers have been collected.