It was about 600 years ago _______the first clock with a face and an hour hand was made.
Andy and Ben both study ________ but they hold opposite ________ views.
China has long been a leader in the field of genetic research ________ improving agriculture.
You lent him $10,000 yesterday? You must ________ by him!
— How do you find the food here? — _______.
Elizabeth _______ a good plan of increasing sales at the meeting.