Where’s Tom? His mother ______ him now.
––Would you mind _______ the music? Your grandpa is sleeping.––Sorry. I’ll do it right away.
––_______ have you been a volunteer? ––Since three years ago.
He has been collecting coins _______ he was seven years old.
She is usually _______. Why did she get ill so suddenly?
Because of Project Hope (希望工程), _______ children have better lives.