1. Tom was about to close the windows _____ his attention was caught by a bird.

A. when         B. If               C. and          D. till

2. _____ they decide which college to go to, students should research the admission procedures.

A. As           B. While            C. Until       D. Once

3. The little boy won’t go to sleep ____ his mother tells him a story.

A. or               B. unless               C. but         D. whether

4. The engineers are so busy that they have zero time for outdoor sports activities, ____ they have the interest.

A. wherever     B. whenever         C. even if     D. as if

5. --Our holiday cost a lot of money.

--Did it? Well, that doesn’t matter ______ you enjoyed yourselves.

A. as long as       B. unless               C. as soon as       D. though