Have you seen a tall boy ______ a basketball ______into the building?
I am too busy now. If I____ free, I ____to the cinema with you.
He doesn’t do his homework________. So he always makes some mistakes.
I find _______difficult to get to sleep because the man upstairs made much noise.
--- You look ______,Paul. What’s the matter?--- I’m having trouble ______ math.
-- I don’t know ______ with this problem. It’s too hard. --- You can ask Mr Wang for help.