1 . __ It is so late. Our son __________ be back .
__ Don’t   worry . I dare say he ________ have some extra work to do.

A．can ; must

B．will ; might

C．should ; must

D．must ; may

2 . ．—What’s the matter with the man hanging his head there?
—Well, if you _______ know, he was caught stealing my bike.

A．must

B．may

C．can

D．shall