Today, we're going to look at ways of discussing a topic. When you're writing or speaking,

you can present facts, or you can use your opinion - but how can you tell the difference?

Today we'll find out.

We're going to listen to a scientist talking about Vitamin D and cancer.

In the clip, see if you can hear both facts and opinions being used.

I believe that the public health problem for vitamin D deficiency is quite significant.

I would estimate minimum 25% of adults in the United States, Europe and probably even

in Australia are vitamin D deficient.

I mean if you think about it, over 250,000 women in the United States will develop breast

cancer this year. Something like 50,000 will die. If 25% of those breast cancers could

have been averted, prevented in some way, just by having a little exposure to sunlight,

would have been really tremendous.

So he was talking about the links between vitamin D and cancer.

Many Australians these days are avoiding the sun, because they know it can cause skin cancer.

But by avoiding the sun, they're missing out on vitamin D - the vitamin that you get from

sunshine, and this is leading to other health problems.

When you're reading, writing or listening to an argument like this, it's important to

be able to tell the difference between statements of fact, and statements of opinion.

But how can you tell the difference?

Well, there are a number of ways you can express your opinion.

Today we're going to look at two of these: using phrases that express an opinion; and

using modal verbs.

First, let's look at some phrases.

The key words to listen for when you're trying to decide whether someone is talking about

facts or opinions are words like believe, think, argue, feel, opinion, or view.

These vary from formal to informal.

If I was talking with my friends, I might say, "I think" or "I believe"

If I was in a class or tutorial, I might say, "In my opinion", or "in my view".

But if I was writing an essay, or giving a very formal talk, I'd probably choose, "it

is believed", or "it is thought".

In formal writing, many people think you should avoid using the word 'I', even if you are

giving an opinion.

Here's the clip again. Listen for some of those phrases.

I believe that the public health problem for vitamin D deficiency is quite significant.

I mean if you think about it, over 250,000 women in the United States will develop breast

cancer this year. Something like 50,000 will die.

Another way we can express opinions is by using modal verbs.

Model verbs express opinions and attitudes. They make statements less certain or less

definite.

They can also be used for recommending and advising.

Here are the modal verbs used for opinions: would

should could

might

These words signal that the speaker is giving an opinion.

Look at these examples. Can you tell which ones are facts, and which ones are opinions?

Fifty thousand will die. Fifty thousand might die.

The second statement uses might - it is an opinion.

Here's another one:

I do not think small amounts of sunlight increase the risk of cancer.

Small amounts of sunlight do not increase the risk of cancer.

In the first statement, you can see 'I do not think'. This is an opinion.

Now look at these 2 sentences:

I believe that vitamin D deficiency might become common among adults.

Vitamin D deficiency will affect 25% of adults.

The first is an opinion - 'I believe', 'might become'.

The second is a fact - 'will affect' 25% of adults.

Now let's watch the clip again - listen for the phrases and modal verbs of opinions.

I believe that the public health problem for vitamin D deficiency is quite significant.

I would estimate minimum 25% of adults in the United States, Europe and probably even

in Australia are vitamin D deficient.

I mean if you think about it, over 250,000 women in the United States will develop breast

cancer this year. Something like 50,000 will die. If 25% of those breast cancers could

have been averted, prevented in some way, just by having a little exposure to sunlight,

would have been really tremendous.

OK, so you can see that Professor Holick is expressing an opinion, using a combination

of phrases and modal verbs.

But now we're going to look at some pronunciation tips.

When you're learning English, there are 3 very important parts of pronunciation. They

are: word stress, sentence rhythm and intonation.

Today we're going to look at the first 2 - how you can practice word stress and sentence

rhythm together, to improve your spoken English.

Listen to this sentence closely for word and sentence stress.

I don't think we should blame moderate, intelligent exposure to sunlight throughout our lives

as the culprit for markedly increasing our risk of developing skin cancer.

Notice that the speaker uses many words with more than one syllable. That is common in

formal academic language.

But when you come across longer words, you have to learn which syllable to stress.

For example, we say: intelligent, increasing, and markedly.

Notice that when you stress one syllable, the vowels in the other syllables are shortened.

Sometimes these short syllables become a schwa - an 'uh' sound - or an 'i'. They're short,

relaxed sounds.

Listen to: moderate

intelligent exposure

culprit markedly

developing cancer

This shortening of syllables preserves the overall sentence rhythm. Listen to the clip

again.

I don't think we should blame moderate, intelligent exposure to sunlight throughout our lives

as the culprit for markedly increasing our risk of developing skin cancer.

So when you're learning to speak English, you need to learn the pronunication of individual

words. But you also need to practice sentence rhythm - putting the words together into sentences.

This is much easier when you get used to shortening the non-stressed vowels.

OK. Listen again to the clip, and then we'll practice some more:

I mean if you think about it, over 250,000 women in the United States will develop breast

cancer this year. Something like 50,000 will die.

If 25% of those breast cancers could have been averted, prevented in some way, just

by having a little exposure to sunlight, would have been really tremendous.

OK, now you can try it. Listen to this sentence:

It would have been tremendous to have averted or prevented significant vitamin D deficiency.

Let's look at each of those words - we'll highlight which syllable is stressed. See

if you can work out how to pronounce each word.

tremendous averted

prevented significant

vitamin deficiency

Now let's see what happens when we put these words back into a sentence.

It would have been tremendous to have averted or prevented significant vitamin D deficiency.

Making your spoken English sound natural takes a lot of practice.

Don't forget to listen closely to vowel sounds and sentence stress, and remember to practice

reading and writing in English every day.

And that's all from me today.

I'll see you next time on Study English. Bye.