51. Unlike most of the worlds volcanoes, they are not always found at the boundaries of the great drifting plates that make up the earths surface; on the contrary, many of them lie deep in the interior of a plate.
[参考译文] 跟世界上的大部分火山不一样的是，它们并不一直在由构成地球 表面巨大漂流板块之间的边界上出现；相反，它们中有很多坐落于一个板 块较纵深的内部。
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 earths interior.
[参考译文] 携带这类国内板块的相对运动已经可以被详细地表述出来，但这类板 块相对于另一些板块的运动还不可以随便地讲解为它们相对于地球内部 的运动。
53. As the dome1 grows, it develops seed fissures2 ; in at least a few cases the continentmay break entirely3 along some of these fissures, so that the hot spot initiates4 the formation of a new ocean.
[参考译文] 暂缺
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 isnt clear that they actually protect the manufacturers and sellers from liability if a customer is injured.
[参考译文] 尽管警告常常是适合而且需要的--譬如对于药物相互用途的危险提出 警告--很多警告还是按州或联邦政府规定需要给出的，然而 并不了解，假如客户受伤时，这类警告是否确实可以使得生产者 和销售者豁免责任。
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 lengthy5 list of possible ones.
[参考译文] 同时，美国法律研究所--由一群法官、律师和理论专家组成，他 们的建议分量极重--发布了新的民事伤害法令指导方针，宣称公司不 必提醒客户注意显而易见的危险，也不必连篇累牍地一再提请他们注意 一些或许会出现的危险。
56. In the past year, however, software companies have developed tools that allow companies to push information directly out to consumers, transmitting marketing6 messages directly to targeted customers.
[参考译文] 但，在过去的一年间，软件公司已经开发出工具，使得公司可以直接 将信息推出给客户，直接把推广讯息传递给目的客户。
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 interactivity7, hospitality, and security will attract online customers.
[参考译文] 像Virtual Vineyards，Amazon．com如此的先驱网站表明，一个将交互性、 热情服务和安全性合理结合以销售相同种类产品的网址是可以吸引网上顾客 注意的。
58. An invisible border pides those arguing for computers in the classroom on the behalf of students career prospects8 and those arguing for computers in the classroom for broader reasons of radical9 education reform.
[参考译文] 有的人为了学生的就业前景为教室里放置电脑而辩，有的人为教育的彻 底改革中更为广泛的原因为教室里放置电脑而辩，这两群人之间有一条 无形的界线。
59. Rather, we have a certain conception of the American citizen, a character who is incomplete if he cannot competently access how his livelihood10 and happiness are affected11 by things outside of himself.
[参考译文] 大家更应该具备的是作为美国公民的某种观念，这个公民人物假如不可以 非常适合地认识到我们的存活和幸福是怎么样遭到自己以外的事物的影响， 那样其公民特点就是不完整的。
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.
[参考译文] 另外，在大家这么一个大国里，经济延展到这么多的州、涉及到这么多 的国际公司，因而要根据数目培养出所需的各类专业职员是不大可能的
61.But,for a small group of students, professional training might be the way to go since well-developed skills, all other factors being equal, can be the difference between having a job and not.
