1 . ---Who can it be that hasn’t handed in his composition?
---It ______ be Robinson. He ______ it in yesterday.

A．will; should hand	B．must; should have handed
C．may; can’t hand	D．can; could have handed

2 . Nuclear ______ be really dangerous at times even though it’s a nice energy in general.

A．shall

B．should

C．can

D．Must

3 . — Isn’t that Ann’s husband over there?
— No, it ________ be him — I’m sure he doesn’t wear glasses.

A．must not

B．can’t

C．won’t

D．may not

4 . Smiles around the world _____ be false, ______ other feelings like anger, fear or worry.

A．must; hide

B．must; hiding

C．can; hide

D．can; hiding

5 . Mr. Bush is on time for everything. How ____ it be that he was late for the opening ceremony ?

A．can

B．should

C．may

D．must

6 . 24. —Who______ it be that is knocking at the door?   
—It ______ be father, but I’m not sure.

A．can; must

B．can; may

C．must; can

D．may; must