21. My cousin has a _______ grasp of what he has learnt, which makes him stand out in every exam.
A. confidential B. conservative C. comprehensive D. compulsory
22. It turns out that ______ we have done a good job of protecting the turtles for the weeks they spend on land, we have neglected the years they spend in the ocean.
A. while B. as C. until D. unless
23. It was within the computer age ______ the term “information society” began to be widely used to describe the context within which we now live.
A. what B. when C. where D. that
24. Researchers are eager to ______ the steadily expanding pool of health information collected from users by products like Fitbit, Clue, and the Apple Watch.
A. tap into B. turn into C. evolve into D. slide into
25. If middle-class Americans continue to struggle ______ as the ultra-wealthy grow even wealthier, it will be increasingly difficult to maintain political support for the free flow of goods and capital across borders.
A. physically B. financially C. emotionally D. artificially
