When you’re learning to drive, _______ a good teacher makes a big difference.
The money ______ you were to buy dog food is gone.
As the final examination is coming , the students are busy ____ it.
He likes the birthday presents ______ his friends gave him.
Upon ______ the office, he saw the message on his desk.
— Where’s Emma? —I can’t say for sure where she is, but she _____ be out shopping.