－I’d like to help the homeless people in the earthquake. －You ________ join a volunteer group. 

---Did they have a good time at the party?---Judging by their smiles, they _________ have enjoyed themselves.

---Look at that girl! Is that Susan?---No , it _______ be her. She has gone back to her hometown.

– May I take the magazine out of the reading room?-- No, you can’t. You            read it here. It’s the rule.

 I felt surprised that anyone of his intelligence   ________  such an easy test.