I hear this kind of CD-ROM is very popular.–Let’s buy one before it ____________.

Yang Liping is famous_________a great dancer.[ ]

How do the students in your school go to school every day?-Most of them go to school _______the school bus.[ ]

I don’t know how to begin a talk with Betty. She can sit all day long ______ a word. [ ]

Would you explain _____?