16.It is no doubt that once ____ this city, you’ll find that there is so much surprise waiting for you to discover. visit B. visiting C. visited D. to visit
After careful consideration, he decided to take the position, ______ he knew it would be difficult for him.
The teacher handed our writings back to us, ______ some necessary changes.
You must ______ that the power is off before you leave the lab.
At such gatherings, people ______ are not necessarily your relatives or friends.
—We’d better go downstairs right now for lunch. —______ They serve food 24 hours a day.