ing the girl, we went into a hall; on __________ walls hung a few pictures of some famous scientists.

Please open the window, Daniel.–_________ I can’t hear you well.

I was worried about my math，but MrBrown gave me an A —______________

It is very important for us parents to be ______ ___in educating children.

Special attention should be _____ to air pollution wherever the factory will be built.