一起烤雅思 1-14a JUNK DNA

steelver (白龍) 路人甲
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发表于:2012-05-18 12:00 [只看楼主] [划词开启]
近期节目传送门~ Episode9 α β Episode10 α β Episode11 α β Episode12 α β
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Today we’re going to look at ‘conditional sentences’. They’re sentences that use ‘if’.

‘If’ you listen carefully, you’ll be able to hear Dr Malcolm Simons talking about junk DNA, the parts of DNA that people used to think were just rubbish. Listen to the different types of sentences he uses.

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

In listening to Dr Simons, you can hear that he uses a variety of sentences. This makes for much more interesting language. You should practice using sentences of different lengths and types, especially complex sentences.

Today we’re going to look at one of the ways you can create complex sentences using an ‘if clause’.

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

They’re often called ‘conditional clauses’.

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

There are a few basic patterns for the ‘if’ clause.

Listen to this.

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

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


‘If’ they can adapt, ‘then’ those that can survive.

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

‘Then’ introduces a clause describing the consequences.

Look at the second example in the extract.

‘If they are there, they have got a function.’

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

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


Let’s look at some more.

‘If you have a university education, then you have more opportunities.’

But the ‘then’ is optional – you can leave it out.

‘If you have a university education, you have more opportunities.’

Notice that this pattern can be reversed.

‘You have more opportunities if you have a university education.’

We never include ‘then’ when the pattern is

reversed like this.

Let’s try with the example from the story.

‘If they’re there, they have a function.’

‘They have got a function, if they’re there.’

OK, now here’s the second pattern for ‘if’ sentences.

This is for when the suggestion is less definite, or less likely.

‘If you had a university education, then you would have more opportunities.’

The pattern here is: ‘if + past tense, then + would + verb’.

‘If you had a university education, then you would have more opportunities.’

We use this pattern when we are talking about the future, and about something that may not be as likely to happen.

Compare these 2 patterns.

‘If you study hard, then you will pass your test.’

‘If you studied hard, then you would pass your test.’

In the first example, it’s a bit like making a useful suggestion.

The second sentence is less definite, and less polite. It suggests that the person doesn’t study hard now.

So that’s 2 ways of making the ‘conditional tense’ – how to say that one thing will happen, or might happen, if something else happens. There are other forms of the conditional tense too.

If you learn them, then your English will improve!
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下一期接着讲另外两种情况~^__^
作业来啦~

答题区

1、If I had been able to work overseas, I ___________ the experience required for the job.
2、If the competitor _____________ its new product, the marketing team would have reached its goal in the last quarter.
3、If the workers go on strike, the train services _________ disrupted.
4、The students _________ more productive, if they work in bright, large classrooms.
5、It might help his prospects, if he _________ the time with the career counsellor.

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