tham khảo:

Sun water and wind are alternative sources of energy．Wind rotating the windmill and moving the sail ．It’s a clean source and a lot of energy ．Unfortunately， if the wind does not blow ．there is no wind energy．As water moves from one place to another ， it makes energy．However， people have to build dams to use this energy source．The dams cost a lot of money ， so water is expensive too.The sun releases large amounts of energy each day．This energy can be converted into electricity .  Solar energy is not only abundant and infinite but also clean and safe.Desfite some drawbacks ， the potention of onternative energy sources is enormous ．However ， how to make full use of the energy resources is a question for researchers all over the world.

Cho bạn nào có câu hỏi giống mình mà vẫn chưa tìm được câu trả lời. Solar energy brings us both benefits and drawbacks. One of the biggest advantages is that it is a renewable energy source. Energy can be produced as the sun lasts forever. Therefore, solar energy can really be called as a long- term energy source. Furthermore, that is a non- energy source of pollutants such as zero carbon dioxide or other gases in electricity generation. Beside those benefits, solar energy also has some drawbacks. The initial installation cost of solar cells is quite high, so not all people can use it. Also, it can not effectively work in cold weather due to the scarcity of sunlight. In conclusion, we can't deny the advantages of solar energy, but it still exists some disadvantages.

Gọi quãng đường của mỗi chặng là S (km)
Quãng đường AB = 3S.
Thời gian đi chặng thứ nhất là: t1 = S/v1 = S/72 
Thời gian đi chặng thứ hai là: t2 = S/v2 = S/60 
Thời gian đi chặng thứ ba là t3 = S/v3 = S/40
Theo giả thiết: t1+t2+t3=4 <=> S/72 + S/60 + S/40 = 4
<=> S(1/72 + 1/60 + 1/40) = 4
<=> S.1/18 = 4
<=> S= 4.18 = 72 (km)
Vậy quãng đường AB là: 3.S = 3.72 = 216 (km)

n our daily life, energy play a very important role, so we should save energy. I think there are many ways to save energy and now I will share with you some ways to save energy effectively. Firstly, we should turn off all the electric appliances when we don't use them such as: lights, fans, air conditioner...… Secondly, we can use solar energy or wind energy instead of electric energy in our house. It will help us save more money. Thirdly, we can go to school or go to work on foot, by bike or by public transport instead of motorbike or car. By these ways, the energy will be saved.

Bài dịch

Trong cuộc sống hằng ngày của chúng ta, năng lượng đóng một vai trò vô cùng quan trọng, vì thế chúng ta nên tiết kiệm năng lượng. Tôi nghĩ có nhiều cách tiết kiệm năng lượng và bây giờ tôi sẽ chia sẻ với các bạn một số cách tiết kiệm hiệu quả. Đầu tiên, chúng ta nên tắt tất cả những thiết bị điện khi không sử dụng như đèn, quạt, điều hòa…. Thứ 2, chúng ta có thể sử dụng năng lượng mặt trời hay năng lượng gió thay cho điện ở trong nhà của chúng ta. Nó sẽ giúp chúng ta tiết kiệm được rất nhiều tiền. Thứ 3, thay vì đi ô tô hay xe máy, chúng ta có thể đi bộ đi học hoặc đi làm. Bằng những cách này, chúng ta có thể tiết kiệm được rất nhiều năng lượng.

xôi vàng là xôi j._.

Solar energy makes us have solar electricity, light to live. If you don't have solar energy, you will have to use electricity, but using electricity will cause a fire, so solar energy is very good.

Energy is very important in our daily life. We use energy for almost everything we do. However energy is limited. We should do the following things to save energy. Firstly, we should use electricity more efficiently. Secondly, we had better reduce our electricity bills. Besides, it’s necessary to turn off the lights when leaving a room or before going to bed to save energy. Moreover, we ought to reduce the use of fossil fuels. In short, we should try our best to save energy for our future and for our planet’s future.

Tham khảo xong lấy ý viết ha :

Nowadays, energy is being run out more and more so it is one of the most important things of our life. We need to save energy because nobody of us can lives without energy. So why don't we start to do it right in our home? We have many ways to save energy in our home. One of those ways is using electricity, water and gas economically. Such as we should turn off the light in room when we go out or in unnecessary situations, avoid wasting water, shut the kitchen stove when stop cooking. Use a microwave instead of a stove to reheat food. Use rechargeable batteries instead of disposable batteries... Besides, we should use electrical equipments which are energy - saving. Such as using lights and fans that have low capacity, or using equipments which reserve electricty. Not only do these help us to save money but also they work effectively.
In addition, we should frequently check electrical equipments in our home in order to fix opportunely. In summary, we need to save energy so that energy isn't run out and continues to serve human's life.

As you know, energy is very important for our life and it is being run out more and more. I think we need to save energy because nobody can live without energy. Firstly, using less energy has lots of benefits – we can save money and help the environment. Energy production requires precious natural resources, such as coal, oil or gas. Therefore, using less energy will help us maintain these resources and make them last longer into the future. Secondly, we can change our means of transportation, if possible, we can walk or ride bicycle instead of taking the car. Finally, we save electricity by turning off all the appliances before going out or going to bed. Another way is to use energy saving light bulbs. Our electricity bill will be reduced by using this way. In short, saving energy is very necessary for our life in modern society. I think we should use them carefully because all of them are limited and they will be exhausted in the future.

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