—Mr Brown , but I'm not sure.
—I'm afraid you can't. It is closed on Monday.
—They be hungry after such a long walk.
—It be our teacher. She has gone to Beijing.
—Yes, dear, but remember that you go with your dad.
—No, you .
—It be cloudy or windy. Who knows?
—Haha! You ___be joking.
—Yes, please.
—It's 8:30 a. m. He (must/can) be at school having classes.
can, may, must, mustn't, needn't, should, have to, had better