The frozen waterfall has attracted floods of tourists to ____ the natural beauty.
A. cherish B. admire C. observe D. discover
Although he has become wealthy, Mr. Wood remains _______ he used to be, modest and friendly.
A. that B. how C. who D. what
Modern plastics can _________ very high and very low temperatures.
A. stand B. keep C. hold D. remain
---What does PM2.5 mean?
--- It’s a professional ______ indicating the condition of air pollution.
A. number B. mark C. term D. item
--- How are things going, Janet?
--- They have set out to deal with the present situation ______ they think deserves their immediate attention.
A. which B. where C. when D. what
--- Do you have the time?
--- Yes. But... my watch is not very __________.
A. efficient B. temporary C. proper D. accurate
