1. --- The Dragon Boat races are so exciting, but our boat is still behind.
--- Don't worry. I am sure our team will win!
A. if B. that C. whether D. why
2. He says he won't be free until tomorrow.
A. that B. if C. whether D. what
3. --- How long does it take to get to the airport?
--- Forty minutes. But it's foggy today. I'm not sure the highway will close soon. Let's set off earlier.
A. whether B. when C. how D. why