21. A to review the factors that affect economic operation

　　22. B the economy of a nation

　　23. C regulation may affect business operation by increasing the cost

　　24. C Because there are too many reasons behind it.

　　25. D cooperate with businessmen and politicians

　　點(diǎn)評(píng)：這是一篇講述經(jīng)濟(jì)運(yùn)行與經(jīng)濟(jì)危機(jī)的論述文�？偡纸Y(jié)構(gòu)。首段用機(jī)器形容經(jīng)濟(jì)體，指出很多因素會(huì)影響經(jīng)濟(jì)發(fā)展，如政府制定的政策法規(guī)，國(guó)際形勢(shì)，人們的態(tài)度等。因?yàn)樵斐山?jīng)濟(jì)衰退的原因是不確定的，所以解決方案同樣具有不確定性。而經(jīng)濟(jì)學(xué)家需要和商人、政客一起合作解決經(jīng)濟(jì)問(wèn)題。本篇文章考查細(xì)節(jié)題為主，盡管文章開(kāi)頭有些抽象，但通篇讀完還是不難理解的。