一起烤雅思 1-14b JUNK DNA

steelver (白龍) 路人甲
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发表于:2012-05-21 12:00 [只看楼主] [划词开启]
近期节目传送门~ Episode11 α β Episode12 α β Episode13 α β Episode14 α
收到热心童鞋的建议,音频将分为小节,方便大家逐页对照,也可以自由轻松的调整学习进度^_^ 碰到不懂的单词请召唤小D喔~


OK, now we’re going to look at ways of making opposites by using prefixes.

Listen to Dr Simons again.

Under Darwinistic notions, you would think that junk would drop off under the theory of natural selection, just like species drop off if they hit ecological niches, which is incompatible with survival. If they can adapt to those niches, then those that can, survive, and those that can’t, die, is the notion.

If you apply that to the DNA sequence, then the coding region genes, which survive, have a function and by the way the non-coding sequences have survived as well.


In the passage we heard the words ‘survive’ and ‘die’. They have opposite meanings.

‘To survive’ means to keep on living and ‘to die’ means to stop living. We call words with opposite meanings ‘opposites’.

Sometimes opposites are formed from the same word stem using prefixes. Two of the prefixes he uses are ‘in’ and ‘non’.

Listen

And by the way the non-coding sequences have survived as well.

He calls the junk DNA the ‘non-coding sequences’.

‘Non-coding’ means not coding. Notice that we use a hyphen with the ‘non-’ prefix.

‘Non-’ usually forms adjectives.

It means ‘not in the group of’, so we have ‘non- European’, ‘non-Aboriginal’ or ‘non-government’.

‘Non-’ can also just means ‘not’, giving a negative sense to a word - ‘non-fiction’, ‘non-smoking’ and ‘non-stick’.

The prefix ‘in’ is used with adjectives as well. It also makes opposites, and means ‘not’.

It forms words like: ‘insignificant’, not significant; ‘inexpensive’, not expensive;

‘intolerant’, not tolerant.

Another common opposite prefix is ‘un-’.

We can have ‘unfair’, ‘unattractive’, ‘unusual’, ‘unnatural’.

But ‘un-’ can also be used with verbs. It means that an action is reversed.

So we have ‘undo’, ‘undress’ or ‘unbend’.


There aren’t many rules about what sorts of words take these prefixes. You’ll have to learn most opposites one by one.

A good way to do this is to try to find out the opposite every time you come across a new word.

Finally for today, let’s have a look at how you can form adjectives from people’s names.

Under Darwinistic notions, you would think that junk would drop off under the theory
of natural selection.


He says ‘under Darwinistic notions’.

‘Darwinistic’ here is an adjective, but it’s got a capital letter – do you know why?

Well, that’s because It comes from the name ’Darwin’ – referring to Charles Darwin, who developed the theory of natural selection.

But it’s got 2 suffixes – ‘-ist’, and ‘-ic’.

The ‘-ic’ suffix forms adjectives that mean belonging to, or like. So ‘Darwinistic’ means ‘like a Darwinist’.

But a ‘Darwinist’?

Well the suffix ‘-ist’ forms adjectives too, but it forms an adjective that describes a type of person with a certain set of beliefs.

When ‘-ist’ is added to people’s names, it means someone who follows that person,

or who believes in what they wrote or said.

So we can have a ‘Darwinist’, someone who believes in Darwin’s theories, or a ‘Marxist’, someone who follows the writings of Marx, or a ‘Buddhist’, someone who follows the teachings of the Buddha.

Well, we’re out of time for today. Remember to watch out for those opposites, and try using ‘if’ clauses.

See you next time. Bye Bye.
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答题区

1、The project would have been viable, if the overhead costs __________.
2、If the quality of air ____________ further, the government will commission an environmental impact study.
3、The company ____________ satisfactorily, if the team had had a strategy in place.
4、If inflation decreases, possibilities for employment __________ enormously.
5、If I were you, I ___________ for the mistake

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