关于无老师听力段子的翻译及理解的问题~~求解答求解答哇~~

小小苏就是我

Professor
That would be Stratigraphy. Stratigraphy isused for dating portable art.  When
archaeologists are digging at a site, theymake very careful notes about which
stratum, which layer of earth theyfind things in. And, you know, the general
rule is that the oldest layers are at thelowest level.  But this only works if thesite
                                                               
hasn’t been touched, and the layers areintact. A problem with this dating method is
that an object could have been carriedaround, used for several generations before it
was discarded.So it might be much olderthan the layer or even the site where it was
found.  （这两句啥意思？被用了很久，所以年代显得更久些？？？）The stratification technique
gives us the minimum age of an object,which
isn’t necessarily its true age.（求翻译）Tom, inyour archaeology class, did you talk about
radiocarbon dating?  

Tom
Yeah, we did. That had to do with chemicalanalysis, something to do with measuring
the amount of radiocarbon that’s left inorganic stuff. Because we know how fast
radiocarbon decays, we can figure out theage of the organic material.  

Professor
The key word there is organic. Is art madeof organic material?  

Tom
Well, you said the lady with the hood wascarved out of ivory. That’s organic.

Professor
Absolutely. Any other examples?

Amy
Well, when they did those cavedrawings.  Didn’t they use, like chacoalor maybe
colors, dyes made from plants?

Professor
Fortunately, they did, at least some of thetime.  So it turns out that radiocarbon
dating works for a lot of prehistoric art.（“证明了同位素标记法对确定很多事前艺术品的日期有用？（是这样翻译的么？）
”这句和上文那个学生的问题有什么关系？？教授没有对学生问题做任何解释呀）
But again there’s a problem. This technique
destroys what it analyzes, so you haveto  chip off  bits of the object for testing.
Obviously we are reluctant to do that insome cases.  And apart from that, there’s
another problems. The date tells you theage of the material, say, a bone or a tree,
the object is made from, but not the datewhen the artist actually created it. So, with
radiocarbon dating, we get the maximumpossible age for the object, but it could be
younger.  
Ok, let’ s say our scientific analysis hasproduced an age range.  Can we narrow it
down?  

Amy
Could we look for similar styles ormotives?  You know, try to find thingscommon to
one time period.  

Professor
We do that all the time.  And when we see similarities in pieces ofart, we assume
some connection in time or place.  But is it possible that we could be imposingour
own values on that analysis?  

Tom
I am sorry. I don’t get your point.  

Professor
Well, we have all kinds of pre-conceivedideas about how artistic styles develop. For
example, a lot of people think the presenceof details demonstrates that the work
was done by a more sophisticated artist.While a lack of detail suggests a primitive
style. But trends in art in the lastcentury or so certainly challenge that idea.  （这句话的意思是反驳前面“越精细越现代”的观点吧？）
Don’t
get me wrong though, analyzing the stylesof prehistoric art can help dating them.
But we need to be careful with the ideathat artistic development occurs in a straight
line, from simple to complexrepresentations.  

Amy（student）
What you are saying is, I mean, I get thefeeling that this is like a legal process, like
building a legal case, the more pieces ofevidence we have, the closer we get to the
truth.
（ 学生的观点是  要建立一个合法的，有据可依的系统来找到真相，这样理解对么？）

Professor
Great analogy.  
And now you can see why we don’t  have an exact date for our
sculpture, the lady with the hood.

小小苏就是我

唉···为啥每次都沉了·····