例41　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.

【结构分析】Unlike most of the world's volcanoes是个介词短语做状语，主谓宾是they are not always found，介词短语at the boundaries of the great drifting plates做状语修饰前面句子，定语从句that make up the earth's surface修饰前面的名词，on the contrary表示转折句，后面是简单句many of them lie deep in the interior of a plate.

【亮点回放】此句话的亮点在于两个介词短语很好的使用，unlike一个介词短语在前面，一个at介词短语在后面，at这个介词短语加上定语从句非常奇妙，后面转折词汇用的不是but，而是很闪光的高分作文转折词汇on the contrary。

【核心词汇】

volcanoes　多数火山

at the boundaries of　边界上出现

the great drifting plates　巨大漂流板块

make up the earth's surface　构成地球表面

on the contrary　相反

deep in the interior of a plate　一个板块较纵深的内部

【参考译文】跟世界上的大多数火山不同的是，它们（热点）并不总是在由构成地球表面巨大漂流板块之间的边界上出现；相反，它们中有许多位于一个板块较纵深的内部。