Your sister isn't at home. Can you help her_______ her baby?
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.
---______________ did you pay for the CD? ---Only nine dollars.