At the beginning of class, the noise of desks______could be heard outside the classroom.
His face looks brown because he works ____ all day.
I'm not sure whether this is the room ________ she left her dictionary.
---Don't put the waste on the ground. ---Oh, I'm very sorry. I ________ the dustbin(垃圾箱) there.
By the time she ________ home, her parents will have prepared some delicious food for her.
---Whose advice do you think I should take? --- ________ .