____ on ten years of observation and study, the story shows that everyone dreams every night, whether they realize it or not.
We’re going to visit so many ______ places and do lots of _______ things .
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.