参考答案:it’s wise of you to show off your greater knowledge in front of the director 答案解析:[解析] 本题考查对形式宾语it及短语show off用法的掌握。本题中think的真正宾语是后面的不定式短语，由于有了宾补wise，故必须由it来充当形式宾语。show off表示“炫耀，卖弄”。
A. To outline contrasting types of economic systems. B. To explain the science of economics. C. To argue for the superiority of one economic system. D. To compare barter and money exchange markets. 参考答案:A 答案解析:[解析] 本题是一道归纳题。这道题要求考生通读全文，归纳出本文的中心大意。本文介绍了三种不同的经济体制，并客观地进行了对比，所以答案为A)。
