IELTS Preparation Series 1, Episode 14: Junk DNA
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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
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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,
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and those that can't, die, is the notion. If you apply that to the DNA sequence, then
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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.
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Let's look at some more.
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If you have a university education, then you have more opportunities.
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But the then is optional - you can leave it out.
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If you have a university education, you have more opportunities.
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Notice that this pattern can be reversed.
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You have more opportunities if you have a university education.
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We never include then when the pattern is reversed like this.
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Let's try with the example from the story.
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If they're there, they have a function.
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They have got a function, if they're there.
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OK, now here's the second pattern for 'if' sentences.
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This is for when the suggestion is less definite, or less likely.
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If you had a university education, then you would have more opportunities.
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The pattern here is: if + past tense, then + would + verb.
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If you had a university education, then you would have more opportunities.
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We use this pattern when we are talking about the future, and about something that may not
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be as likely to happen.
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Compare these 2 patterns.
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If you study hard, then you will pass your test.
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If you studied hard, then you would pass your test.
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In the first example, it's a bit like making a useful suggestion.
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The second sentence is less definite, and less polite. It suggests that the person doesn't
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study hard now.
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So that's 2 ways of making the conditional tense - how to say that one thing will happen,
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or might happen, if something else happens. There are other forms of the conditional tense
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too.
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If you learn them, then your English will improve!
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OK, now we're going to look at ways of making opposites by using prefixes.
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Listen to Dr Simons again.
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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,
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and those that can't, die, is the notion.
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If you apply that to the DNA sequence, then the coding region genes, which survive, have
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a function and by the way the non-coding sequences have survived as well.
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In the passage we heard the words survive and die. They have opposite meanings.
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'To survive' means to keep on living and 'to die' means to stop living. We call words with
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opposite meanings, opposites.
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Sometimes opposites are formed from the same word stem using prefixes. Two of the prefixes
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he uses are 'in' and 'non'.
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Listen:
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And by the way the non-coding sequences have survived as well.
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He calls the junk DNA the non-coding sequences.
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Non-coding means not coding. Notice that we use a hyphen with the non- prefix.
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Non- usually forms adjectives.
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It means 'not in the group of', so we have non-European, non-Aboriginal or non-government.
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Non- can also just means not, giving a negative sense to a word - non-fiction, non-smoking
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and non-stick.
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The prefix 'in' is used with adjectives as well. It also makes opposites, and means 'not'.
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It forms words like: insignificant, not significant; inexpensive, not expensive; intolerant, not
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tolerant.
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Another common opposite prefix is un-.
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We can have unfair, unattractive, unusual, unnatural.
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But un- can also be used with verbs. It means that an action is reversed.
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So we have undo, undress or unbend.
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There aren't many rules about what sorts of words take these prefixes. You'll have to
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learn most opposites one by one.
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A good way to do this is to try to find out the opposite every time you come across a
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new word.
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Finally for today, let's have a look at how you can form adjectives from people's names.
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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.
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He says under Darwinistic notions.
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Darwinistic here is an adjective, but it's got a capital letter - do you know why?
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Well, that's because It comes from the name 'Darwin' - referring to Charles Darwin, who
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developed the theory of natural selection.
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But it's got 2 suffixes: -ist and -ic.
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The -ic suffix forms adjectives that mean belonging to, or like. So 'Darwinistic' means
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like a Darwinist.
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But a 'Darwinist'?
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Well the suffix -ist forms adjectives too, but it forms an adjective that describes a
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type of person with a certain set of beliefs.
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When -ist is added to people's names, it means someone who follows that person, or who believes
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in what they wrote or said.
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So we can have a Darwinist, someone who believes in Darwin's theories, or a Marxist, someone
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who follows the writings of Marx, or a Buddhist, someone who follows the teachings of the Buddha.
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Well, we're out of time for today. Remember to watch out for those opposites, and try
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using 'if' clauses.
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See you next time. Bye Bye.
