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IELTS Preparation Series 1, Episode 14: Junk DNA


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0:00

Hello. I'm Margot Politis. Welcome to Study English, IELTS preparation.

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Today we're going to look at conditional sentences. They're sentences that use 'if'.

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If you listen carefully, you'll be able to hear Dr Malcolm Simons talking about junk

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DNA, the parts of DNA that people used to think were just rubbish. Listen to the different

0:37

types of sentences he uses.

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Under Darwinistic notions, you would think that junk would drop off under the theory

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of natural selection, just like species drop off if they hit ecological niches, which is

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incompatible with survival. If they can adapt to those niches, then those that can, survive,

1:02

and those that can't, die, is the notion. If you apply that to the DNA sequence, then

1:09

the coding region genes, which survive, have a function, and by the way the non-coding

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sequences have survived as well. So the proposition would have to be that if they're there, they've

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got a function.

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In listening to Dr Simons, you can hear that he uses a variety of sentences. This makes

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for much more interesting language. You should practice using sentences of different lengths

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and types, especially complex sentences.

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Today we're going to look at one of the ways you can create complex sentences using an

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'if clause'.

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An 'if clause' is a phrase that gives a condition that's necessary for something else to happen.

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They're often called conditional clauses.

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If means when, provided that, or on condition that.

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There are a few basic patterns for the 'if clause'.

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Listen to this:

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If they can adapt to those niches, then those that can, survive, and those that can't, die.

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So the proposition would have to be that if they're there, they've got a function.

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If they can adapt, then those that can survive.

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The pattern here is: if + simple present tense verb, then ….

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Then introduces a clause describing the consequences.

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Look at the second example in the extract.

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If they are there, they have got a function.

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Notice that the then is left out in this example. Then is optional.

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He could have said if they are there, then they have a function.