IELTS Mock Test 2024 April

PART 2

Host: Hello and welcome to today’s talk. Here with me is the famous botanist. Professor Alison Downing. So, Alison, tell us something about cocoa beans.

Alison: Cocoa beans, also called cacao beans, are the primary constituent in making chocolate. Grown in tropical areas in South and Central America, West Africa and Asia, the cocoa tree is often raised on small, family-owned farms. When the harvested pods are opened to expose the beans, the pulp and cocoa seeds are removed and the rind is discarded. The pulp and seeds are then piled in heaps, placed in bins, or laid out on grates for several days. During this time, the seeds and pulp undergo a process called ‘sweating’, where the thick pulp liquefies as it ferments. The fermented pulp trickles away, leaving cocoa seeds behind to be collected. This is when the beans are harvested and then the bags holding them are ready to be transported.

But the most important step in processing the cocoa bean is cleaning it. Once the beans are unloaded from the railroad cars, the packages are opened and then weighed by machines. Then the pods are split, and the seeds or beans are covered with a sweet white pulp or mucilage. On arrival at the factory, the cocoa beans are sorted and put in a hopper to be cleaned more rigorously. The wet beans are then transported to a facility so they can be fermented and dried. They are fermented for 4 to 7 days and must be mixed every 2 days. They are dried for 5 to 14 days, depending on the climate conditions. The fermented beans are dried by spreading them out over a large surface and constantly raking them.

Then the beans are ready to be roasted. Now, roasting takes place at a high temperature and then the beans are boiled in a heated chamber. During the roasting process the beans will be expanded and cracked. But prior to this, the beans are trodden and shuffled about using bare human feet. During this process, red clay mixed with water is sprinkled over the beans to obtain a finer colour, polish, and protection against molds during shipment to factories in the United States, the Netherlands, the United Kingdom, and other countries. Now, back to what I was saying. After the beans are cracked, they need to be cooled. Then the roasted beans are sealed in pockets.

Host: Wow, that is not a simple process, is it? But someone told me that different roasting levels of coffee can lead to different kind of flavours.

Alison: Yes. Roasting coffee transforms the chemical and physical properties of green coffee beans into roasted coffee products. The roasting process is what produces the characteristic flavour of coffee by causing the green coffee beans to change in taste. Unroasted beans contain similar if not higher levels of acids, protein, sugars, and caffeine as those that have been roasted, but lack the taste of roasted coffee beans due to the Maillard and other chemical reactions that occur during roasting. The vast majority of coffee is roasted commercially on a large scale, but small-scale commercial roasting has grown significantly with the trend toward ‘single-origin’ coffees served at specialty shops. Some coffee drinkers even roast coffee at home as a hobby in order to both experiment with the flavour profile of the beans and ensure the freshest possible roast. So here, I am going to introduce some of these roasted coffee beans and their special flavours.

Now, the First Crack is lighter-bodied, and has a higher acidity level with no obvious roast flavour, and is popular for its special mild taste. This level of roast is ideal for tasting the full original character of the coffee. The Green Beans are raw, unroasted coffee beans. They are strictly hard beans with a smoky flavour and are slightly acidic. We’ve also got French Roast. And the flavour that comes across in French roast coffee usually has more to do with the roasting process than the actual quality of the beans. By the time the beans are dark enough to qualify as French, most of their original flavour has dissipated. In its place come the flavours of caramelising sugar, bittersweet coffee, and often, a bit of chocolate. And finally, Espresso Smoky. That is coffee brewed by forcing a small amount of nearly boiling water under pressure through finely ground coffee beans. Espresso is generally thicker than coffee brewed through other methods, has a higher concentration of suspended and dissolved solids, and has crema on top. As a result of the pressurised brewing process, the flavours and chemicals in a typical cup of espresso are very concentrated. Espresso is also the base for other drinks such as a cafe latte, cappuccino, cafe macchiato, cafe mocha, flat white, or cafe Americano...

PART 3

Student F = Student Female; Student M = Student Male

Lecturer: Thank you all for coming here today to hear about the Moa, a kind of animal which has been extinct for a long time. Well, first of all we’ll look at what the Moa are. The Moa are nine species of flightless birds endemic to New Zealand. They were the dominant herbivores in New Zealand’s forest, shrubland and subalpine ecosystems for thousands of years, but around 500 years ago, they all went extinct. When I mention extinct animals during ancient times, you may immediately think of dinosaurs, which disappeared around 66 million years ago. Fossils of dinosaurs which we use to study are large in number, but not many of those of Moa remain, though both animals appeal to people today.

Student F: So the Moa sound more mysterious now. But sir, I’ve got a question about these flightless birds. How can we distinguish them from other birds?

Lecturer: That’s a good question! Birds are commonly characterised by being warmblooded, having feathers and wings usually capable of flight, and laying eggs, while the flightless Moa. until their extinction, were the largest birds in the world. Their heads are relatively small in relation to their bodies, and they are the only wingless birds lacking even the vestigial wings and substantial tail bones in their family.

Student M: That’s impressive. But were they born to be like that? I mean when they were chicks.

Lecturer: Yes, absolutely! So let’s move onto the chicks. The eggs of Moa were laid in nests and incubated for about two months. The chicks would be well-developed upon hatching and probably would be able to leave the nests to feed on their own almost immediately.

Student F: I’ve heard that the male Moa are thought to have incubated the eggs. Is that true?

Lecturer: I think there is a possibility for that. I’ve read somewhere that the sex-specific DNA recovered from the outer surfaces of eggshells suggested that these eggs were likely to have been hatched by the male, but we still need to consult more.

But I have a question. There has been some occasional speculation that the Moa were still alive, because someone said they had caught sight of them in New Zealand in the late 19th century or even the 20th. Do you think it’s possible?

Student M: I’m not amazed by that, since that kind of thing has been claimed several times, but I find it funny because no reliable evidence of Moa tracks has ever been found, and experts still contend that Moa survival is extremely unlikely.

Student F: So what was the reason for the Moa’s extinction? I wonder if it was global warming or some other factors related to their living environment.

Lecturer: Well, before the arrival of human settlers in New Zealand, the Moa’s only predator was the massive Haas’s eagle. Then the Maori arrived sometime before CE 1300, and all Moa genera were soon driven to extinction by hunting. What a horrible thing!

Lecturer: All right. Now let’s look at the features of some species of Moa. The South Island Giant Moa may have been the tallest birds ever known, and the second tallest of the nine moa species is the North Island Giant Moa, with the females being markedly larger than males both in weight and height.

Student M: And I’ve heard that the smallest of the Moa birds are the Coastal Moa. Is that right?

Lecturer: Yes, you’re right. And have you heard about any other kinds of Moa before?

Student F: I know the Crested Moa. The eggs they laid may be larger than others’.

Lecturer: As they mainly lived in the remote interior of the Southern Island, their fossils are rare or absent in archaeological sites, and no egg remains have yet been identified.

Student F: Are there any species of Moa that have got more fossils?

Lecturer: Yes, of course. A considerable amount of remains of the Stoutlegged Moa exist, due to the well-preserved properties of their habitat. Their skulls reveal relatively bad vision, a good sense of smell, and a very short bill.

Then there is the Eastern Moa. They were remarkable in having very long and narrow windpipes, which probably enabled them to make louder, more resonant calls than those of other Moa, and have the greatest vocal abilities, so they could communicate when they could not see each other in the forest or at night. They used a range of senses, apart from sound in their search for food, such as their sense of smell and vision.

PART 4

Good morning, everyone. Today, I’m going to talk about the research project I’ve been involved in on time measurement.

Do you know how time is measured? Consider how we measure length, and how with time we encounter a difficulty. Before we could grasp it, it would slip through our fingers. In fact, as we can see, we are forced to have the recourse to measure something else—the movement of something in space, or a set of movements in space. All the methods that have been employed so far really measure time by a motion in space. The measurement of time is no easy matter; a scientific unit only arrives at after much thought and reflection.

As the most primitive form of measurement, the sun seems to be natural. Ever since man first noticed the regular movements of the sun and stars, we have wondered about the passage of time. Prehistoric people first recorded time according to the sun’s position. To start off, let us take noon, which is when the sun is on the meridian at the highest point of its course across the heavens, and when it casts the shortest shadow. But this measurement, which was regarded as a major one in ancient times, was less important than the natural events that occurred.

The earliest natural events that had been recognised were in the heavens, but during the course of the year there were many other events that indicated significant changes in the environment. Seasonal winds and rains, the flooding of rivers, the flowering of trees and plants, and the breeding cycles or migration of animals, all led to natural divisions of the year, and further observation and local customs led to the recognition of the seasons.

Years later, precise measurements were invented, because the passage of time was extremely important for astronomers and priests who were responsible for determining the exact hour for daily rituals and for important religious festivals. Apart from the connection with religion, accurate time measurement was also related to the government, since they divided the day or the night into different periods in order to regulate work and various events. For thousands of years, devices have been used to measure and keep track of time. The current sexagesimal system of time measurement, dates back to approximately 2000 BCE from the Sumerians. It was found that the earliest ancient time keepers were mainly invented and used in Mesopotamia, where the water clock was introduced from, as well as in North Africa, especially in the area of ancient Egypt.

So now, I’d like to introduce you to some of the most well-known ancient timekeepers, as well as the disadvantages of them, for which they were replaced by various new forms of clocks that were used afterwards.

A sundial is a device that tells the time of day by the apparent positioning of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate and a gnomon which casts a shadow onto the dial. As the sun appears to move across the sky, the shadow aligns with different hour-lines which are marked on the dial to indicate the time of day. However, it was quickly noted that the length of the day varied at different times of the year, therefore there could have been a difference between ‘clock time’ and ‘sundial time’. In addition, the sundial was of no use at night, so a water clock was invented.

The water clock, or clepsydra, appeared to have been invented around 1,500 BCE and was a device which relied on the steady flow of water from or into a container. Measurements could be marked on the container or on a receptacle for the water. It was reliable, but the water flow still depended on the variation of pressure and temperature from the top of water in the container.

As the technology of glass-blowing developed, from some time in the 14th century, it became possible to make sandglasses. Originally, they were used as a measure for periods of time like lamps or candles, but as clocks became more accurate they were calibrated to measure specific periods of time. The drawback however, as you can imagine, was the limited length of time they could measure.

The last timekeeper to be introduced is the fire candle clock. Candle clocks take advantage of a simple concept: the slow and consistent nature of a burning wax candle. By utilising this process, our ancestors were able to keep steady track of the time. The clocks were created by engraving the length of the candle with evenly spaced markings. Each marking represented a single unit of time, and as the wax burned down, each hour would disappear. However, the draughts and the variable quality of the wax mainly influenced the time of burning. Like oil lamps, candles were used to mark the passage of time from one event to another, rather than tell the time of day...