prep1-3 句子结构

3.         (24557-!-item-!-188;#058&001027)

Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil, their descendants, popularly known as killer bees, had migrated as far north as southern Texas.

(A) Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil,

(B) In less than 35 years since releasing African honeybees outside Sao Paulo, Brazil,

(C) In less than the 35 years since African honeybees had been released outside Sao Paulo, Brazil,

(D) It took less than 35 years from the release of African honeybees outside Sao Paulo, Brazil, when

(E) It took less than the 35 years after the time that African honeybees were released outside Sao Paulo, Brazil, and then

我的问题是：

1）这个句子的结构是什么，Less than 35 years after 在句中的成分是什么

2）关于主句使用过去完成时，请问有什么线索可以确定用这个时态吗？是after吗？

3）release 在这里怎么翻译呢？

谢谢指教。

thanks.

我之前看过他的解释。就解释过去完成时这个问题的话，这个说法和语法中的“after表示以过去时间为起点的一段时间以后，且通常与过去时态连用”多少可以作为佐证。但，始终觉得哪里不对。

再请教

1）than是介词，Less是代词/量词，表示少量，修饰35years，朗文上有例子：less than 10/100 etc ：a distance of less than 100 metres；35 years after ...是介词短语做时间状语

2）35 years after the release 表示过去的一段时间，不再延续；作为对比，since这样从过去开始一直延续。有since引导的时间状语，主句用现在完成时；35年的结束的那个时间点，相对作者而言已经是个过去时间点了，就是这个时间点决定了谓语用过去时，而migrate的动作是在一段时间内发生，所以用过去完成时。------- 其实我同意alohabrian 的说法 --------  RPurewal蛮清楚的 --------  希望我的表述没有起副作用

3）release就是释放的意思，可能是巴西因某种原因从非洲引入了这个物种，在不到35年的时间内，这个物种就向北迁徙到南德州了。

非常感谢。

关于1）

我也找了些句子，比如，（before/after的成分在这里一样）

If an object that requires a permit for permanent export entered Canada less
        than
        35
        years before its proposed export, the export permit must be issued automatically, and cannot be refused.

less
        than
        35
        years before its proposed export 做时间状语。

less than 具有形容词和副词词性，这里我认为是形容词词性--adj+n+after(prep)--形容词短语作时间状语。

不知对否，请NN继续指正。

关于2）的解释也更清楚了。

谢谢alohabrian 和Mayanist

Less than

The Grammar Book (p.728) states that
"Separation of  fewer from the head noun encourages the
use of less" followed by the
example of "less than 50 people". So let's finally consider the case
of less than. There are 142 examples
of less than in MICASE, only five of
which are adverbials like "women are paid less than men". Of the
remaining 137, 97 (71%) have singular or uncountable complements. Therefore,
some 40 instances remain to be accounted for.

Around 10 are
clear cases where fewer would be
formally preferred, and would most likely be chosen in writing:

5) and I think
there's less than a hundred of these left,

6) and then there's
been less than a hundred cases total in the past seven years

7) there's like less
than five other places in Europe

8) now way at the
bottom, less than ten thousand bucks

9) in United States
less than five percent of the C-E-Os are women.

On the other hand,
there would seem to be a rather different rule that applies to certain
mathematical or numerical calculations, a number of which are quite common in
some speech events:

10) the order must
be less than or equal to ten, by Fermatt's theorem.

11) the probability
that X is less than six

12) photoelectrons are
scattered forward at less than forty degrees.

Less in these cases seems to be
operating as "some lower number than", as in:

10a) the order
must be ten or some lower number than ten, by Fermatt's theorem.

Finally, there are
cases like:

13) it'll go
through in less than ten seconds

This seems
perfectly reasonable if we interpret it as:

13a) it'll go
through in less time than ten seconds

Rather than:

13b) it'll go
though in fewer seconds than ten.

Since the great
majority of these instances of less than with plural complements were
spoken by faculty or senior graduate students, in this case there is no real
evidence of any generational shift in usage.