When you read the book, you’d better make a mark _____ you have any questions.
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.