51. Unlike most of the world's volcanoes, they are not always found at the boundaries of the great drifting plates that make up the earth's surface; on the contrary, many of them lie deep in the interior of a plate.

　　[參考譯文]跟世界上的大多數火山不同的是，它們(熱點)并不總是在由構成地球表面巨大漂流板塊之間的邊界上出現;相反，它們中有許多位于一個板塊較縱深的內部。

　　52. The relative motion of the plates carrying these continents has been constructed in detail, but the motion of the plates with respect to another cannot readily be translated into motion with respect to the earth's interior.

　　[參考譯文]攜帶這些大陸板塊的相對運動已經能夠被詳細地表述出來，但是這些板塊相對于另一些板塊的運動還不能輕易地解釋為它們相對于地球內部的運動。

　　53. As the dome grows, it develops seed fissures (cracks); in at least a few cases the continent may break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean.

　　54. While warnings are often appropriate and necessary--the dangers of drug interactions, for example--and many are required by state or federal regulations, it isn't clear that they actually protect the manufacturers and sellers from liability if a customer is injured.

　　[參考譯文]盡管警告常常是適當而且必須的--比如對于藥物相互作用的危險提出警告--許多警告還是按州或聯邦政府規定要求給出的，然而(我們)并不清楚，如果顧客受到傷害時，這些警告是不是確實可以使得生產者和銷售者豁免責任。

　　55. At the same time, the American Law Institute--a group of judges, lawyers, and academics whose recommendations carry substantial weight--issued new guidelines for tort law stating that companies need not warn customers of obvious dangers or bombard them with a lengthy list of possible ones.

　　[參考譯文]與此同時，美國法律研究所--由一群法官、律師和理論專家組成，他們的建議分量極重--發布了新的民事傷害法令指導方針，宣稱公司不必提醒顧客注意顯而易見的危險，也不必連篇累牘地一再提請他們注意一些可能會出現的危險。

　　56. In the past year, however, software companies have developed tools that allow companies to "push" information directly out to consumers, transmitting marketing messages directly to targeted customers.

　　[參考譯文]但是，在過去的一年間，軟件公司已經開發出工具，使得公司可以直接將信息"推出"給顧客，直接把營銷訊息傳遞給目標顧客。

　　57. The examples of Virtual Vineyards, Amazon.com, and other pioneers show that a Web site selling the right kind of products with the right mix of interactivity, hospitality, and security will attract online customers.

　　[參考譯文]像Virtual Vineyards，Amazon.com這樣的先驅網站表明，一個將交互性、熱情服務和安全性合理結合以銷售同類商品的網址是可以吸引網上客戶注意的。

　　58. An invisible border divides those arguing for computers in the classroom on the behalf of students' career prospects and those arguing for computers in the classroom for broader reasons of radical education reform.

　　[參考譯文]有些人為了學生的就業前景為教室里放置電腦而辯，有些人為教育的徹底改革中更為廣泛的理由為教室里放置電腦而辯，這兩群人之間有一條無形的界線。

　　59. Rather, we have a certain conception of the American citizen, a character who is incomplete if he cannot competently access how his livelihood and happiness are affected by things outside of himself.

　　[參考譯文]我們更應該具有的是作為美國公民的某種觀念，這個公民人物如果不能很恰當地認識到自己的生存和幸福是如何受到自身之外的事物的影響，那么其公民特征就是不完整的。

　　60. Besides, this is unlikely to produce the needed number of every kind of professional in a country as large as ours and where the economy is spread over so many states and involves so many international corporations.

　　[參考譯文]另外，在我們這么一個大國里，經濟延展到這么多的州、涉及到這么多的國際公司，因而要按照數量培養出所需的各類專業人員是不大可能的