在PTE中,无论是Summarise Spoken Text 还是 Re-tell Lecture的考题大都是从真实的讲座或者演讲中截取的中间经常经常夹杂很多不同的环境音.很多同学都反映有时未必是听不懂,而是听不到. 鉴于此,墨尔本悉尼文波雅思PTE专门为大家总结了真实讲座的PTE练习音频,相比新闻音频来说,整体更加接近PTE考试的真题,内容方面,我们也会为大家提供考试中存在的近似题,最近我们会持续更新,敬请期待!
下面是墨尔本悉尼文波PTE雅思培训学校为大家整理的原文材料：
What’s up guys it’s Bucky and welcome to your fifth biology tutorial and in this tutorial I want to answer the question that I asked you guys that at the end of last video and that is why are we learning about acids and bases it seems like it’s kind of like chemistry term and we’re talking about biology so what the heck? Well, remember a couple of tutorials ago I said that every living thing is made up of these smaller living things called cells. Now a cell is essentially just a bundle of chemicals. It’s just organised in a very specific and organised kind of way. Now in the last video I said an acid is a molecule that splits apart in water and whenever it do it released a hydrogen ion H+. Now a base is essentially the same thing except the base splits part in water it releases hydroxide which is OH-. The important thing to remember is that these are charged particles and a cell remember is basically just a bunch of chemicals organised in a very specific careful kind of way. Now if you’re familar with chemistry and chemical reactions you know that any time you want to mess up a chemical you need to throw some charged particles into the mix and that’s what happens whenever you have charged particles from acids and bases in your body so whenever you drink a bunch of battery acid or eat a bunch of baking soda this is what happens – the molecules are going to split apart and cause these charged ions and they’re going to react with the chemicals inside the cells and they’re either going to break apart the chemical bonds or mess them up in some kind of way and that is why it’s usually not a good idea to drink battery acid. So just remember that because of acids and bases causing charged particles they interfere with the chemical bonds in living organisms and mess them up or sometimes they don’t kill the cells completely but they can cause diseases in the organisms and I’m going to be talking about those specific diseases later on. But for right now this is all you have to remember. Now on the topic of, you know, acids, bases in charge particles, I want to show you guys something really cool that’s going to help you remember these charged particles. And that is, well, just think about this: well, what do happen whenever you do have an acid or base in your body? Your body needs to kind of correct that problem or get rid of it somehow so say that you had an acid-like H+ which is a hydrogen ion in your body, how would your body get rid of it? Well, what your body does it actually combines it with the product from a base which is remember OH-, in other words a hydroxide so whenever you combine this and this, check out what happens? We end up with, can you guys guess? H2O, freaking water. How amazing is that? And I show this to people all the time and they’re kind of, well kind of amazed in a way because it’s kind of weird that obviouly your body needs water you should drink a lot of water all the time and it’s very beneficial to your body. However, whenever you have the product from an acid or base, such as a hydrogen ion or a hydroxide, that it’s so harmful to your body. However, when these two combine they form something that’s very beneficial to your body so, you know you really don’t need to remember this but it’s kind of cool understanding the two harmful things from acids and bases can form something so beneficial to your body and you know just cool little thing that you can remember.
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