第2题: [单项选择]五环三萜皂苷元中齐墩果烷型和乌索烷型的主要区别是 A. 基本骨架不同 B. A/B环稠和方式不同 C. D/E环稠和方式不同 D. E环上两个甲基的位置不同 E. A环上两个甲基的位置不同 参考答案:D 答案解析:齐墩果烷型E环上两个甲基在 20位，乌索烷型19和20位各有一个。
第5题: [单项选择]_________ still young, Mr. George has had amazing achievement in cosmology. A. When B. As C. Although D. Since 参考答案:C 答案解析:让步状语从句。乔治虽然年轻但他已在宇宙论上取得了惊人的成就。▲这是一个省略句，补全后应为Although he is still young．．．。although引导让步状语从句，表示“虽然，尽管”
第16题: [单项选择](Overseas) travel sounds (excited) and sometimes (exotic) but not everyone can afford (it). A. Overseas B. excited C. exotic D. it 参考答案:B 答案解析:[解析] excited“激动的，兴奋的”，一般用来形容人，而exciting才表示“令人兴奋的”。所以应将excited改为exciting。
第36题: [单项选择]The author indicates that the towns in the South ______. A. still have higher house prices than those in the North B. are all recorded a drop in house prices C. are narrowing the gap of the average property D. have become the most desirable places to live in 参考答案:A 答案解析:推理题。题目问的是：作者暗示南部的城镇______ 。文章第八段提到：But the South remains more expensive， although the gap is narrowi
