单选题 What did Juan Louis learn from the analysis of his audience?

A、 Some of them had once experienced an earthquake.
B、 Most of them lacked interest in the subject.
C、 Very few of them knew much about geology.
D、 A couple of them had listened to similar speech before.

【正确答案】 C

【答案解析】解析：细节题。文章第二句话提到From his audience and analysis he learned that only 2 or 3 of his classmates knew much of anything about geology．(根据听众和分析，他得知自己的同学中只有两三个人对地质学稍微了解。)选项C“几乎很少有人了解地质学”符合原文。其他选项文中均未提及，因此C是正确答案。

单选题 How did Juan Louis start his speech?

A、 By reflecting on Americans' previous failures in predicting earthquakes.
B、 By noting where the most severe earthquake in U. S. history occurred.
C、 By describing the destructive power of earthquakes.
D、 By explaining some essential geological principles.

【正确答案】 B

【答案解析】解析：细节题。本题问“他如何开始自己的演讲”，文中提到he decided to begin by noting that the most severe earthquake in American history took place not in California or Alaska but at New Madrid, Missouri in 1811．(他决定从讲解1811年发生在密苏里州新马德里——美国历史上最严重的大地震，而不是加利福尼亚或阿拉斯加的地震开始说起。)选项B“从美国历史上发生过的最严重的地震说起。”符合题意。选项A“反映之前美国预测地震失败的例子”；选项C“描述地震的损伤力”；选项D“解释一些必要的地质学原理”。文中均未提及，因此B为正确答案。

单选题 What did Juan ask his roommate to do when he was making his trial speech?

A、 Interrupt him whenever he detected a mistake.
B、 Focus on the accuracy of the language he used.
C、 Stop him when he had difficulty understanding.
D、 Write down any points where he could improve.

【正确答案】 C

【答案解析】解析：细节题。本题问“他试讲时让自己的室友做什么?”根据文章中他对室友说的话，“Stop me，”he said，“any time l 8ay something you don’t understand．”(他说：“只要你听不懂的时候就打断我。”) C“只要理解有困难的时候就打断他”符合题意。A“发现错误时打断他”；B“重点看他使用的语言是否正确”；D“写下任何能让他进步的点”，均与原文不符，因此C为正确答案。