Although you may meet some difficuIties,you should never .
-Do you know_______ second-hand smoke?-To protect our health and memory.
It's foggy today. I'm not sure _______ the highway will be closed soon.
_______ the students_______ their teacher know about the four people.
Super Brain is_______ an interesting TV program_______ many people like watching it.
My mother keeps all the things in my family in good order. She is_______.