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Nowadays, amid the storming development of high-tech devices such as smartphones or e-book readers, people seem to neglect the existence of certain inventions that date back thousands of years. One of those is the mirror.

People grew a desire to see themselves as they saw their reflections in the surface of water. Around the 600s BC, the first mirrors were made from natural materials such as polished stones. After a while, people started to use bronze, gold and silver to make mirrors. These metals were heavy, so mirrors had very modest sizes. Ruling-class people, especially ladies, used them as a fashionable accessory. Hardly did they go out without a mirror. In the 1st century, the first glass mirrors were invented by the Romans and were made bigger to allow people to look at the whole body. However, not everyone cherished the mirror. Some people were irritated to find themselves ugly looking at the mirror, and there were rumors that what they saw in the mirror were reflections of sins and demons.

Nowadays, despite technological advancement, mirrors still play important roles in various modern-day fields, such as surgery, transport, architecture and so on. In fact, mirrors are utilised in technology and have inspired the inventions of several devices such as cameras or satellites.

What were the first materials for making mirrors?

Read the passage and do the tasks that follow.

Li-Fi Technology

   Li-Fi technology is a new technology that transmits signals as light instead of radio waves. In urban areas where Wi-Fi networks become congested and there is a lot of noise in the signals, this technology is something that can be of immense use to an individual. The basic requirement of this technology is the available of light!

    Light is also an electromagnetic wave like radio waves. The only difference is that the former  has the ability to transmit data almost ten thousand times faster than latter! The basic process is quite simple to understand. An LED light bulb, any one at all, can be flicked on and off in order to be able to generate signals. A light sensor on a device picks up the digital information sent by the LED, which enables it to be processed by a computer.

     The question is whether anyone wants to go through the annoying experience of sitting under a flickering light bulb. This is the interesting part. The technology is focusing on make sure that the light bulb is flickered up to billions of times a second!  At that rate, the human eye simply cannot notice the light bulb being flicked on and off.

     However, everything comes with a disadvantage. The major disadvantage here is the fact that these signals cannot penetrate walls. So if you want to move from one room to another, you will need to have a wired bulb present in that room as well.

   An Estonian startup company called Velmenni took the technology out of the laboratories and brought it into the real-world offices, and industrial environments in Tallinn for the first time.

    Overall, this sounds like quite a development in the field of communication technology.

The Advantages of Using Wi-Fi on Your Smartphone

Wi-Fi is a method for devices such as smartphones to connect wirelessly to the Internet using radio waves. Connecting to the Internet using Wi-Fi requires a hotspot, but it is always faster than the 3G cellular networks which smartphones can also use to connect, and occasionally faster than 4G. Using Wi-Fi when it is available can also prove to be cheaper and make your phone run more efficiently in the long run than relying on cellular networks.

When you use a Wi-Fi network to access the Internet from your phone, the data usage does not count against your bundled data. Mobile providers often allocate a certain amount of data for free each month and charge you a fee for any data usage beyond this. By connecting via Wi-Fi wherever it is available, you can save your bundled data for situations when you might not be close to any Wi-Fi hotspots.

In many situations, your speed using a strong, dedicated Wi-Fi connection is faster than that of using your mobile network. It is very noticeable when transferring larger files. If you need to download large files or stream media to your smartphone in a hurry, it is much better to do so via Wi-Fi.

Battery life is extremely important for smartphones because you will not be able to connect to the Internet or use certain functions such as the camera flash if your battery is too low. Using Wi-Fi to connect to the Internet drains less battery life than using a mobile network, especially in situations where the cellular coverage fluctuates. Since Wi-Fi is generally faster than using mobile networks, you will also not spend as much time transferring the data, which further decreases battery usage.

The following are the advantages of using Wi-Fi on your smartphone EXCEPT that          _______.

The Advantages of Using Wi-Fi on Your Smartphone

Wi-Fi is a method for devices such as smartphones to connect wirelessly to the Internet using radio waves. Connecting to the Internet using Wi-Fi requires a hotspot, but it is always faster than the 3G cellular networks which smartphones can also use to connect, and occasionally faster than 4G. Using Wi-Fi when it is available can also prove to be cheaper and make your phone run more efficiently in the long run than relying on cellular networks.

When you use a Wi-Fi network to access the Internet from your phone, the data usage does not count against your bundled data. Mobile providers often allocate a certain amount of data for free each month and charge you a fee for any data usage beyond this. By connecting via Wi-Fi wherever it is available, you can save your bundled data for situations when you might not be close to any Wi-Fi hotspots.

In many situations, your speed using a strong, dedicated Wi-Fi connection is faster than that of using your mobile network. It is very noticeable when transferring larger files. If you need to download large files or stream media to your smartphone in a hurry, it is much better to do so via Wi-Fi.

Battery life is extremely important for smartphones because you will not be able to connect to the Internet or use certain functions such as the camera flash if your battery is too low. Using Wi-Fi to connect to the Internet drains less battery life than using a mobile network, especially in situations where the cellular coverage fluctuates. Since Wi-Fi is generally faster than using mobile networks, you will also not spend as much time transferring the data, which further decreases battery usage.

By using Wi-Fi, you _______.

The Advantages of Using Wi-Fi on Your Smartphone

Wi-Fi is a method for devices such as smartphones to connect wirelessly to the Internet using radio waves. Connecting to the Internet using Wi-Fi requires a hotspot, but it is always faster than the 3G cellular networks which smartphones can also use to connect, and occasionally faster than 4G. Using Wi-Fi when it is available can also prove to be cheaper and make your phone run more efficiently in the long run than relying on cellular networks.

When you use a Wi-Fi network to access the Internet from your phone, the data usage does not count against your bundled data. Mobile providers often allocate a certain amount of data for free each month and charge you a fee for any data usage beyond this. By connecting via Wi-Fi wherever it is available, you can save your bundled data for situations when you might not be close to any Wi-Fi hotspots.

In many situations, your speed using a strong, dedicated Wi-Fi connection is faster than that of using your mobile network. It is very noticeable when transferring larger files. If you need to download large files or stream media to your smartphone in a hurry, it is much better to do so via Wi-Fi.

Battery life is extremely important for smartphones because you will not be able to connect to the Internet or use certain functions such as the camera flash if your battery is too low. Using Wi-Fi to connect to the Internet drains less battery life than using a mobile network, especially in situations where the cellular coverage fluctuates. Since Wi-Fi is generally faster than using mobile networks, you will also not spend as much time transferring the data, which further decreases battery usage.

A Wi-Fi connection offers  ________.

The Advantages of Using Wi-Fi on Your Smartphone

Wi-Fi is a method for devices such as smartphones to connect wirelessly to the Internet using radio waves. Connecting to the Internet using Wi-Fi requires a hotspot, but it is always faster than the 3G cellular networks which smartphones can also use to connect, and occasionally faster than 4G. Using Wi-Fi when it is available can also prove to be cheaper and make your phone run more efficiently in the long run than relying on cellular networks.

When you use a Wi-Fi network to access the Internet from your phone, the data usage does not count against your bundled data. Mobile providers often allocate a certain amount of data for free each month and charge you a fee for any data usage beyond this. By connecting via Wi-Fi wherever it is available, you can save your bundled data for situations when you might not be close to any Wi-Fi hotspots.

In many situations, your speed using a strong, dedicated Wi-Fi connection is faster than that of using your mobile network. It is very noticeable when transferring larger files. If you need to download large files or stream media to your smartphone in a hurry, it is much better to do so via Wi-Fi.

Battery life is extremely important for smartphones because you will not be able to connect to the Internet or use certain functions such as the camera flash if your battery is too low. Using Wi-Fi to connect to the Internet drains less battery life than using a mobile network, especially in situations where the cellular coverage fluctuates. Since Wi-Fi is generally faster than using mobile networks, you will also not spend as much time transferring the data, which further decreases battery usage.

Using Wi-Fi offers longer battery life because           _______.

The Advantages of Using Wi-Fi on Your Smartphone

Wi-Fi is a method for devices such as smartphones to connect wirelessly to the Internet using radio waves. Connecting to the Internet using Wi-Fi requires a hotspot, but it is always faster than the 3G cellular networks which smartphones can also use to connect, and occasionally faster than 4G. Using Wi-Fi when it is available can also prove to be cheaper and make your phone run more efficiently in the long run than relying on cellular networks.

When you use a Wi-Fi network to access the Internet from your phone, the data usage does not count against your bundled data. Mobile providers often allocate a certain amount of data for free each month and charge you a fee for any data usage beyond this. By connecting via Wi-Fi wherever it is available, you can save your bundled data for situations when you might not be close to any Wi-Fi hotspots.

In many situations, your speed using a strong, dedicated Wi-Fi connection is faster than that of using your mobile network. It is very noticeable when transferring larger files. If you need to download large files or stream media to your smartphone in a hurry, it is much better to do so via Wi-Fi.

Battery life is extremely important for smartphones because you will not be able to connect to the Internet or use certain functions such as the camera flash if your battery is too low. Using Wi-Fi to connect to the Internet drains less battery life than using a mobile network, especially in situations where the cellular coverage fluctuates. Since Wi-Fi is generally faster than using mobile networks, you will also not spend as much time transferring the data, which further decreases battery usage.

The word “drains” in the last paragraph is closest in meaning to ______.

Read the passage and choose the best answer.

When the era of digital technology has bloomed all over the world, human beings have witnessed thousands of wonderful inventions which can be applied in a variety of fields. Among those, robots are considered as a brilliant human creativity and have been developed further to serve people. Shaped into human bodies, robots are machines built to do tasks. Normally, they can be controlled by built-in computers so that they can do a series of automatic actions. These human-like machines help us explore new places, and uncover the mystery of the deep and cold ocean which is very dangerous for a normal body. They seem to play an unlimited role not only in exploration, but in medical fields as well. In hospitals, they can do a wide range of jobs in cooperation with doctors to improve the health care system. For instance, robots can assist physicians remotely to check on patients and even inspect them. They can search around hospitals to collect information about the sick and transmit it to the doctors through a screen to help them interact efficiently. With cutting-edge technology they can even do an operation with a high level of accuracy under professionals’ control. Thanks to robotic assistants, medical workers can save time and save many lives from fatal diseases. It is believed that the number of robots applied in the medical industry will be expected to increase dramatically over the next few years.

What is the passage mainly about?