1. —Who came out _______ first in the race of 800 meters?
—It was Jack. He’s always ________ first to reach the line.
A. the; the B. \；\ C. the; \ D. \; the
2. The small river _______ I visited three years ago has been seriously polluted recently.
A. where B. which C. what D. when
3. I did remember _________ the door before leaving the office, but forgot to turn off the lights.
A. locking B. having locked C. to lock D. to have locked
