17. Parents cannot take care of them ________, so children should learn to be independent.
A. all the time B. at one time C. in no time D. at any time
18. _________ is the ability to do the job rather than where you come from or what you are that matters.
A. It B. That C. This D. There
19. The purpose of our advertising is to _________ customers’ attention to our product.
A. pay B. devote C. fix D. draw
20. The professor’s research finally proved to be ______, though he had spent a lot of money on it.
A. priceless B. valuable C. worthless D. worthwhile
