These dresses are quite different____those.[ ]

I’ve got a lot of apples. I don’t know what I’ll do _______ them.[ ]

Bicycling is a good exercise;________ it does not pollute the air.

The light in his office is still on. Do you know _______?—To prepare for the material(材料) the meeting will need tomorrow, I think.

He usually_____a lot of money on books.