Could you tell us ______ happens when one student in class expresses a personal opinion _______ maybe upsets other students?

They walked _____ the forest and got to a small village. [ ]

What a room they own (拥有)!

The boy was so ______ in reading that he didn’t hear his father knocking at the door.

It’s ______ of you to bring me some fruit.—My pleasure. Please make yourself at home, sir.