Will people use money_____100 years?
________________ a book in the library, enter a key word into the computer.
Studying in groups is necessary _________________ you want to do well in school.
---Whose is the pencil box? ---It ____________ be Tom’s. Look at his name on the cover!
Could you record the football game for me? I can’t watch ____________ later.
Martha is a _______________ girl. She always smiles and says hello to others.