May I ask you ________ questions?

— I heard they went skiing in the mountains last winter. — It ________ true because there was little snow there.

The students        be in the classroom because there are lights in it.

Sometimes smiles around the world ______ be false, hiding other feelings like anger, fear or worry.

—Is Jessica giving us a speech this evening?—No, it _________ be her．She _________ to Japan．