第30题: [单项选择]The third paragraph suggests that ______. A. modern dams are all made of concrete B. Romans once built many great dams C. there was too much water in Iraq in the past D. modern dams are better than early dams 参考答案:B 答案解析:由第三段最后“The Romans were great dam-builders...”(罗马人曾是伟大的大坝修建者)可推知答案“罗马人曾经修建了很多宏伟的大坝”。[A]与原文细节“现代大坝通常是由