095.It is one of nature’s great ironies that the availability of nitrogen in the soil frequently sets an upper limit on plant growth even though the plants’ leaves are bathed in a sea of nitrogen gas.
=It is one of nature’s great ironies/ that the availability of nitrogen/ in the soil/ frequently sets an upper limit on plant growth/ even though the plants’ leaves are bathed in a sea of nitrogen gas.
*自然界 大的矛盾之一/就是氮供给/土壤中的/通常限定了一个上限植物生长的/，尽管植物的叶子沉浸在一片氮气的海洋中。
*这个句子很容易理解，但是很有意思，关键词是 irony，主要是搞清楚 irony 的内容是什么。
096.Unless they succeed，the yield gains of the Green Revolution will be largely lost even if the genes in legumes that equip those plants to enter into a symbiosis with nitrogen fixers are identified and isolated，and even if the transfer of those gene complexes，once
they are found， becomes possible.
=Unless they succeed/，the yield gains of the Green Revolution/ will be largely lost/ even if the genes in legumes/ that equip those plants to enter into a symbiosis with nitrogen fixers/ are identified and isolated/，and even if the transfer of those gene complexes/，once they are found， becomes possible.
#除非他们成功/，否则产量收入绿色革命的/将在很大程度上损失/，即使豆科植物中的基因/它为植物创造条件进入共生系统和固氮细菌(共生)/可被辨识出来和分离开来/，即使转移这些基因综合体，一旦被发现之后，成为可能。
*这个句子融入了有关基因方面的专业知识，读起来有点困难，但是句子的顺序减小了句子的难度，句子开句明意，even if 的内容有补充说明的作用，所以句子的大
意还是很容易理解的。
097.Its subject(to use Maynard Mack’s categories)is "life-as-spectacle，" for readers， diverted by its various incidents，observe its hero Odysseus primarily from without;the tragic Iliad，however，presents "life-as-experience"：readers are asked to identify with the mind of Achilles，whose motivations render him a not particularly likable hero.
=Its subject/(to use Maynard Mack’s categories)/is "life-as-spectacle"/， for readers/， diverted by its various incidents/，observe its hero Odysseus/ primarily from without; the tragic Iliad/，however/，presents "life-as-experience"/：readers are asked to identify with the mind of Achilles/，whose motivations render him a not particularly likable hero.
#其主题(若借鉴 Maynard Mack 的分类)/是“人生如景象”，对读者来说/被种种事件所分散/，观察其主人公 Odyssus/主要是从外部/;悲剧《伊利亚特》/，然而/，表现的却是“人生如经历”/：读者需要与 Achilles 产生共鸣/，其动机使他成为一个不是特别惹人喜爱的主人公。
*这个句子讲的是文学方面的内容，相信很多同学会感到要真正理解句子意思要了解相关的文学作品，所以读起来有点困难，但是只理解句子的大意还是不难的，有一处要特别注意，即 identify with 是与……相联系的意思，类似的短语要注意积累。
098.Most striking among the many asymmetries evident in an adult flatfish is eye placement： before maturity one eye migrates，so that in an adult flatfish both eyes are on the same side of the head.
=Most striking/ among the many asymmetries/ evident in an adult flatfish/ is eye placement/： before maturity one eye migrates/，so that in an adult flatfish both eyes are on the same side of the head.
#令人惊奇的/在很多不对称特征中/成年比目鱼身上明显的/，是眼睛的位置/：在成年前一只眼睛移动/，因此成年比目鱼两只眼睛均位于头部的同一侧。
*这个句子的结构有点乱，严格的说应该是两个句子，但我们只看内容不看语法，所以不用管它的结构。
099.The best evidence for the layered-mantle thesis is the well-established fact that volcanic rocks found on oceanic islands，islands believed to result from mantle plumes arising from the lower mantle，are composed of material fundamentally different from that of the midocean ridge system， whose source，most geologists contend，is the upper mantle.
= The best evidence for the layered-mantle thesis/ is the well-established fact/ that volcanic rocks found on oceanic islands/，islands/ believed to result from mantle plumes/ arising from the lower mantle/，are composed of material/ fundamentally different from that of the midocean ridge system/， whose source/，most geologists contend/， is the upper mantle.
#好的证据/对于地幔分层论来说/是这样一个确凿的事实/即火山岩石在海洋岛屿上发现的/，这些岛屿被认为是 mantle plume(形成的)/从下层地幔升上来的/，是由物质构成/与中部海脊的物质根本不同的/，其成因/，大多数地质学家认为/，是上部地幔。
*这个句子融入了地理方面的专业知识，对于这样的句子，我们要重点理解大意，而不要强求找到每个专业词汇的确切意思，有些单词认识就反映不认识就过去。
100.Some geologists，however，on the basis of observations concerning mantle xenoliths， argue that the mantle is not layered，but that heterogeneity is created by fluids rich in "incompatible elements" (elements tending toward liquid rather than solid state) percolating upward and transforming portions of the upper mantle irregularly， according to the vagaries of the fluids’ pathways.
但是，某些地质学家，以对地幔捕虏岩体(xenolith)所作的观察为依据，指出地幔并非是分层排列的，相反，地幔的异质性是由那些富含“不相容成分”的流质构成的，这些成分趋向于流体而非固体的状态，自下而上渗透扩散，并依照这些流质流向的任意性，不规则地将上部地幔的某些部分予以改变。