21.－How long do you think it will be ______ they repair the car?
－Perhaps two or three hours.
A. when B. until C. once D. before
22. Since the new technology was brought in, the burden of the workers in our factory ______ little.
A. has become B. became C. is becoming D. had become
23. On the wall hung some photos of the house owner in the frame, _______ caught my eye and I went for a closer look.
A. one of them B. both of whom C. one of which D. both of which
24. If he doesn’t improve his learning methods, I’m afraid there will be a danger _______ he could fall further behind others.
A. that B. what C. which D. when
25. _______ to hiring himself out in my company, my former boss felt very depressed.
A. reducing B. reduced C. having reduced D. being reduced
26. Whether to study abroad or run a company with her friends ______ a difficult dilemma for
her now.
A. was B. were C. is D. are
27. It is universally acknowledged that pink flowers are often chosen for mothers, ________ purity,
