By giving the example of a downturn in the economy, what does the author want to show?

(单选题)Professor Wang, ______ for his informative lectures, was war (单选题)In recent years, much more emphasis has been put ______ deve (单选题)“Perhaps we need to send for Dr. Smith to see what we can do (单选题)A lot of language learning, ______ has been discovered, is h (单选题)China has been pushing the reform of public hospitals ______ (单选题)A number of high buildings have arisen ______ there was noth (单选题)Can you tell the ______ difference between the words “requir (单选题)The monkeys of the circus always give very funny and interes (单选题)Stanley has a strong sense of responsibility; as soon as he (单选题)The cleaner was on the spot and saw what really happened, so