Most whales must come up for air after several minutes, _______ a few can stay under water for an hour or more.
A. while B. or C. for D. so
The numbers that researchers get from the experiments can be _______, just like number puzzles.
A. disappointing B. inspiring C. worrying D. confusing
_______ the house is empty, memories flood my mind of a time when it was filled with life.
A. Since B. Unless C. As if D. Even though
By the time a child is five, he _______ hundreds of hours of television.
A. will watch B. will have watched C. had watched D. is watching
There is nothing wrong with using a credit card for purchases. It’s more _______ than carrying loads of cash.
A. convenient B. valuable C. sensitive D. innocent
If not _______, you’re allowed to return everything within 10 days for a full refund and no further duties.
A. to satisfy B. being satisfied C. satisfied D. satisfying
