Name: 學習英語 - 系列一，第16集：DVT (Study English - Series 1, Episode 16: DVT)
Uploaded: 2021-01-14T07:45:27.000Z
Duration: 10 min 3 s
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Hello, and welcome again to Study English, IELTS Preparation. I'm Margot Politis.

情態副詞

If you've been on a flight recently, you will have heard about the danger of sitting still

for a long time in an aeroplane, apart from the danger of boredom that is!

The danger is from a condition called deep vein thrombosis, or DVT.

Today on Study English we'll listen to a doctor talk about DVT, then we're going to look at

how to talk about things that might happen in the future.

Deep vein thrombosis is where a clot forms in the calf veins and occasionally in the

veins of the leg, sometimes in the veins of the pelvis, and this is a great concern because

the clot may dislodge, travelling with the flow of blood into the right side of the heart

When we're travelling on long haul flights, several things happen. First of all, we're

stationery. We're not moving our legs, so there's no physiological compression of the

calf muscles. Blood tends to sit in the veins and may clot.

Number two, the environment is dry. We dehydrate, we may drink some alcohol. We dehydrate even

further. Alcohol's a diuretic agent, and it results in us actually drying out, and that

makes the blood a little bit thicker and stickier, and these factors lead to clotting.

Sometimes, in perhaps particularly the economy section of an aeroplane, we may be a little

bit cramped and our leg may be slightly compressed on the seat. This could further prevent blood

flow back to the heart and trap blood in the leg, where clotting may occur.

Dr Crantock was talking about things that that could happen, may happen, or perhaps

Perhaps is an adverb. It is a word like maybe or possibly. It gives a statement the sense

that the speaker is not sure if the thing will happen.

Perhaps I will means the same as possibly I will, or maybe I will.

May has a number of meanings. The most common use is when you are asking permission.

But the other use of may is to talk about possibilities in the future.

I may come in tomorrow means in the future, I will possibly come in, but it's not definite.

"When I was little I could swim," means when I was young, I was able to swim.

But could is also used to express future possibilities.

It could rain tomorrow. It's not definite, but it might rain.

Dr Crantok is talking about what can happen sometimes on flights, but it won't definitely

Sometimes, in perhaps particularly the economy section of the aeroplane, we may be a little

flow back to the heart and trap blood in the leg, where clotting could occur.

So for speculating, or thinking about what will happen in the future, we can use adverbials

we can use modal verbs like may and could

and we can use phrases like I guess, I imagine, I suspect.

So in the clip he says blood clotting could occur.

Notice that the adverbials can occur in a number of places in the sentence.

Listen to Dr Crantock and the way he structures his argument. Listen for a topic sentence,

and for the way he lists the different ideas.

The first sentence is the topic sentence. He said: When we're travelling on long haul

So we know from this topic sentence, that he is going to tell us about travelling on

But there are lots of things you can say about travelling on long haul flights. So he says

something else in this sentence that gives us more information. He says several things

This phrase is called the controlling idea. Every topic sentence has a controlling idea.

It tells us what the focus of the paragraph will be.

So he's going to be discussing several things that happen on long haul flights.

In the rest of the paragraph, he lists some of the things that happen. He raises the points

one by one, and discusses them in detail.

Dr Crantock says first of all, we're stationary.

This is the first factor in his argument. People are stationary, or sitting still.

He says: Number two, the environment is dry. This indicates it is the second factor in

Moving on through the argument, you can keep discussing factors by using transition signals

You could also use next, but this is quite informal as well.

The last reason or item in the list could be introduced by lastly or finally.

It is good practice to watch out for these transition devices when listening to someone

talk. They'll help you follow an argument more clearly.

Finally for today, let's look at some definitions. Doctor Crantock gives a definition of the

condition he is talking about, because it's an unusual medical term.

veins of the leg, sometimes in the veins of the pelvis.

He says: Deep vein thrombosis is where a clot forms in the calf veins.

This is common pattern for giving a definition.

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學習英語 - 系列一，第16集：DVT (Study English - Series 1, Episode 16: DVT)

phrase

physical

slightly

pattern