TPO61听力Lecture3原文+MP3+题目+答案下载

TPO61听力Lecture3听力原文+MP3+题目+答案

在分享TPO61听力之前，其他三个单科已经更新完了，阅读的小伙伴可直接点击：

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TPO61听力Lecture3原文：

listen to part of a lecture in a food science and technology class.

one of the most popular beverages worldwide is coffee. You're probably not surprised to hear that. here in the united states, for example, more than half of the adult population drinks at least one cup of coffee every day. for various reasons. Some of those who drink coffee choose to drink decaffeinated coffee either some of the time or all of the time. so the coffee industry had to face this sort of need or demand for decaffeinated coffee. taking caffeine out wasn't a problem. It was actually taking the caffeine out without changing the flavor of the coffee or without increasing the health risk to drinking the coffee. and although coffee has been decaffeinated for probably just about a century at this point, and there's one relatively new method that's fairly commonly used these days to decaffeinate coffee, and that's super critical, fluid extraction, super critical fluid, big word.

It's on the board. We can't understand the process of extracting the caffeine from the coffee. If we don't get this concept down. Pat, in order to do that, let's take a look at the phase diagram. This should be a review. so the phase diagram, it shows the conditions of pressure and temperature at which a substance exists in 1 of 3 faces, a solid, a liquid, and a gas. so we've got pressure on the vertical axis, temperature on the horizontal. and as you know, a substance will change its phase. If you start changing temperature or pressure, for example, if we choose sort of an arbitrary pressure right about here, and keep the pressure constant and increase the temperature, we start as a solid, but as you can see, just follow the line going to the right. as we increase the temperature, the solid changes to a liquid, and then changes to a gas. and that's what we would expect. We certainly know that happens with ice. It goes from a solid to a liquid and to a gas. if we keep the pressure constant, now let's do it the other way and keep the temperature constant.

。。。。此处省略800字！

TPO61听力Lecture3部分题目：

1. What is the main tope of the lecture?

A A method of packing coffee at high pressure and temperature

B A method of decaffeinating coffee while preserving its flavor

C Reasons why carbon dioxide is added to caffeinated soft drinks

D The critical importance of carbon dioxide for the food industry

2. How does the professor organize the review of the phase diagram?

A By using an example of water vapor gradually changing to solid ice

B By showing phase changes that occur when pressure and temperature increase at the same time

C By first showing temperature-induced phase changes and then showing pressure-induced phase changes

D By first explaining the properties of gas and then introducing the properties of supercritical fluids

3. Under what conditions do supercritical fluids form?

A When a solid begins turning into a liquid

B When a very hot gas is put under high pressure

C When certain solids dissolve in certain liquids

D When a liquid is allow temperature but under high pressure

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