（二）句型结构：

1. There they have found greater comfort and security than they would have in the open.

他们发现在洞穴里生活要比在野外更舒适，更安全。
（1）这句包含了由than引导的比较状语从句，比较的双方是there 指 in caves 与 in the open 在野外，露天，参见短语部分。从句中省略了comfort and security, than 引导的比较状语从句常可承前省略主句中已出现的成分。
例：The environment of the countryside is much more beautiful than that of the city. 乡村的环境要比城里好得多。
I'm afraid that I can't do better than he (has done).
（2）从句中的would have (done) 是虚拟语气形式，表示一种想像的结果，而非事实。
例：If we had gone by car, we would have saved time.如果我们乘车去，我们就会节省时间。
If we could have stopped, there wouldn't have been an accident. 如果我们能够停下来，就不会发生事故了。

2. Yet there are advantages to underground life, too, and something to be said for imagining whole cities, even mankind generally moving downward: of having the outermost mile of the Earth's crust honeycombed with passages and structures, like a gigantic ant hill.

然而生活在地下也有好处，因而有理由设想将整座城市，甚至全人类搬到地下去；将地壳表层一英里厚的地方建满通道和建筑物，就像一个巨大的坟冢，这会给人类带来许多好处。
（1）something 这里指某些理由，好处等，to be said for/of 指可以说到的，能提出来的；for相对于against 尤其有为……说话，支持……之意。
例：There is something to be said for his proposal. 他的提义有一些理由。
（2）(for) imagining…与（of）having… 都是动名词短语作介词宾语。其中imagine sb. /sth. doing 想像某人/某物做（某事）；have sth. done使某物如何。
例：Can you imagine living on the moon? 你能想像在月球上生活吗？
She has the sitting-room decorated with some famous paintings. 她把客厅用一些名画装饰起来。

3. The vast amounts of energy now expended in warming our surface surroundings when they are too cold, and cooling them when they are too warm, could be saved.

我们的地表环境太冷时，需要增温，太暖时，又需降温，这耗费了大量能量，搬到地下生活，则可省下这部分能量。
这句话的主要部分是 The vast amounts of energy could be saved. Expended…是过去分词短语代替定语从句 which is expended…，这一分词短语中又包含了when 引导的时间状语从句；in warming (cooling) 是介词+现在分词的用法。
例：In trying to catch the criminal, he was seriously wounded. 在试图抓住歹徒时，他受了重伤。
关于过去分词作定语。
例：The textbook used in our department is very successful. 我们系所选用的教科书非常成功。

4. The whole world could be on eight-hour shifts, starting and ending on the stroke everywhere, at least as far as business and community endeavors were concerned.

全世界都可以实行八小时轮班制，各地都可能做到同时上班，同时下班，至少公务活动和社会活动可以如此。
（1）这句话是虚拟语气。could be表示对未来情况的一种想像或假设，on the stroke参见短语部分。
（2）as far as… is (are) concerned, 意为take… into consideration 考虑到……，就……而论，也可用so far as… concerned。
例：As far as your interest is concerned, I have no comment to make. 考虑到你的兴趣，我没有什么可说三道四的。
例：as far as sb. is concerned 是 in one's opinion 指某人的意见
As far as I am concerned, you can do whatever you like. 就我而论，你可以随心所欲。

5. Even where are windows, what is the prospect one views (if one bothers to) but sun, sky, and buildings to the horizon-plus some limited greenery?

即使有窗户，又能看到什么景象呢（如果你特意去看的话）？只是太阳、天空以及一望无际的建筑物--加上一点有限的绿色植物而已。
（1）where there are windows = in the buildings which have windows。where这里是关系代词，代替the place。
例：Where there is a will, there is a way. 有志者事竟争。
（2）but 介词，只有，除了……什么也没有，等于only, except。
例：He is so poor that he has nothing but money. 他是如此贫穷以至于除了钱以外什么也没有。

6. …but however carefully restricted the upward trips might be, the chances are that the dwellers of the new caves would see more greenery, under ecologically healthier conditions, than dwellers of surface cities today.…

但不管向上的旅行受到多么严格的控制，新洞穴里的居民将有可能比今天生活在地表的居民在更为健康的生态环境下生活，并见到更多的绿色植物。
（1）however… might be 是让步状语从句。在正式语体中，所有引导让步状语从句的连词后面的现在时，都可以用may代替。
例：However brilliant you are/may be, you can't know everything. 不管你有多么聪明，也不可能什么都知道。
（2）(the) chances are that……是非正式用法，意为"可能"
Chances are that he's already heard the news. 他很可能已得知了这个消息。
（3）than 引导比较状语从句，比较的双方是dwellers of the new caves 与 dwellers of surface cities。