What class are you ________ ?A.in B.at
Ten minutes ago, there______ an eraser, a pen and some books on the desk.
— You have found your lost umbrella, haven’t you?—Yes. I _____ it behind the door this afternoon.
This morning I had hardly got to my school when it_____ to rain.
---A number of volunteers______ willing to teach in China`s rural areas.---Yes, the number is getting_______.
Food safety is becoming ______ than before. More and more people care about it.