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 continentmay break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean.

　　[參考譯文] 暫缺

　　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 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。

來源:可可英語 http://www.ccdyzl.cn/cet4/201006/105564.shtml