Now they have had special cages made to protect them from these monsters.
如何解读，怎么分析？
（取自新概念II Lesson 90 What's for supper?）

Now they have had special cages (which are) made to protect them from these monsters. @贵阳新思路英语 

我不知道楼主困惑的是什么部分：
如果是：made to protect them from these monsters.那么是过去分词作定语意思上相似于定语从句的被动语态

如果是have had或者直接用have区别不大。时态问题可以穿插

前一句：
Oil rigshave to be repaired frequently and divers, who often have to work in darkness ahundred feet under water, have been frightened out of their wits by giant fishbumping into them as they work.
Now theyhave had special cages made to protect them from these monsters.

这。。楼上大神的意见不敢苟同。整个句子连起来，have done是现在完成时没问题，至于have had不是指拥有的意思，have something done是一个固定用法，就类似”把XX事情搞定”这样的意思。比如have your homework done，比如have my car fixed，等等。后面to protect那部分是表”have cages made”的目的。大概这样

手机打得太辛苦了我还是爬起来用电脑吧。。
我的理解是这样的：
骨干：They make special cages.
换个说法（固定用法）：They have special cages made.
加状语表目的：They have special cages made to protect them from these monsters.
变成现在完成时加上个时间状语now：Now they have had special cages made to protect them from these monsters.
我觉得这样写出来比较便于分析结构嗯~~

用到了一个固定搭配have sth (cages)down(made)让某物被做，to do 不定式表目的性（……是用来做……的），protect sth from保护某物

句子是错的

6/7 楼该是正解。
"Have" can be followed by:
a) object + infinitive (without "to")
b) object + -ing
c) object + participle
1) Causative: Have something done = cause something to be done by somebody else. The past participle has a passive meaning.
e.g. I must have my watch repaired. (= I want my watch to be repaired.)
e.g. I'm going to have my hair cut this afternoon.
e.g. If you don't get out of my house I'll have you arrested.
2) Experience: Have + object + past participle can also be used in the sense of "experience". Again, the past participle has a passive meaning.
e.g. We had our roof blown off in the storm.
e.g. King Charles had his head cut off.

其实这一句蛮有讨论价值的，但似乎没几个人认同或在意，所以我只好 来个寂寞孤独的总结，简单交代草草了事算了，悲催......
我只是业余语法爱好者，没包袱，没光环，也把胜负当屎尿，所以不认同我的分析和论点，不妨轻松自在地加入讨论。
原句：Now they have had special cages made to protect them from these monsters.
乍看之下"made to protect them from these monsters"似乎是修饰cages的分词短语（participle phrase）；但换了一个角度，又似乎该这么解读："Now they have had special cages made" 而"to protect them from these monsters 则成了目的状语"。
那该如何厘清这模棱两可的状况呢？关键就在于谓语动词的时态......
事实是，那些潜水员现在已有了一些特制的笼子来保护他们。
考虑以下两个状况：
（1）假设谓语动词是“have”：
Now they [have] special cages (made to protect them from these monsters). (made...monsters)这一段也只能是修饰cages的分词短语了。因为“Now they have special cages made”显然是没有这个必要，那几个已制作好的笼子可以重复使用，不需再重复叫人制作新的笼子，如此解读不符实情。
（2）如果谓语动词是“have had”：
合理的解说也只能是 Now they have had special cages made (to protect them from these monsters). 他们叫人制作了特别的笼子+（目的状语）：
他们过去叫人制作了一些特别的笼子/ They had special cages made
所以，现在他们已叫人制作了特别的笼子/Now they have had special cages made
如果想说“他们现在拥有特制笼子”，一般会说 “now they have special cages” 而不说“now they have had special cages"（要讨论这个分别将牵涉到静态动词和动态动词方面的领域，需要更多篇幅，所以就此打住）
交代完毕。


have sth done 使役式的一般式 使某事被做
have had sth done 使役式的完成式 已经使某事被做 这里的第一个have是助动词
will have sth done 使役式的完成式 将使某事被做
理解的时候可以理解为they have special cages made 他们使笼子被做出来
to protect them from these monsters. 不定式作目的状语
protect sb from sth/sb 保护某人某事免受...之害

整个句子很简单。唯一是have had ..made 的模糊性。
有两种可能的解释。had something made 根据前后文，这种连结法的解释是错的。

如何判定是哪一种？
比如 have my hair cut. 这里cut 一定是跟着 have. 否则没有意义。
但 have special cages 就足够了。后面只是说明其用途而已。

Now they have had special cages made to protect them from these monsters.
这样你就明白了
Now they have had special cages(which is ) made to protect them from these monsters.

挖 使劲挖

哈哈哈， 澳洲那位卖羊皮的仁兄何在？“小楼一夜听春雨”在此向您谦卑的求助！