When I got into the classroom, I found a book ______ on the floor.

Funny jokes can make us ________when we are sad..

— It is so hot in the classroom. Would you mind ____ the windows?—OK. I’ll do it right now.

-- It’s a bit cold. Would you mind my ________ all the windows?--- Do as you like ,please.

My pen pal Andrew found it difficult ______ Chinese well