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20 tháng 7 2018
I. SỰ GIAO THOA - NGUỒN SÁNG KẾT HỢP. 
            1. Nguyên lý chồng chất. 

TOP

            Ðó là nội dung của nguyên lí chồng chất. Nguyên lí chồng chất chỉ đúng đối với các sóng ánh sáng có cường độ yếu (ánh sáng do các nguồn sáng thông thường phát ra). Ðối với sóng Laser, vì cường độ điện trường của chúng rất lớn do đó có sự tương tác giữa các sóng với nhau và nguyên lí chồng chất không còn đúng nữa. Nguyên lí chồng chất là nguyên lí cơ bản để nghiên cứu hiện tượng giao thoa và nhiễu xạ.

1 tháng 10 2021

         Students should play sports because it helps strengthen bones and muscles. Firstly, physical activity is very good for children's bone development, helps keep bone density at a high level, and reduces the risk of osteoporosis. Secondly, When we exercise, the brain releases a chemical that creates feelings of happiness and helps relieve stress. Beside, participating in a team sport will give your child the opportunity to meet many new friends, with different ages and personalities. As you see, sport not only brings health and dynamism, sports also help children develop teamwork, cooperation skills, discipline, ... and focus better during class!

11 tháng 9 2018

Bảng tuần hoàn các nguyên tố hóa học, hay bảng tuần hoàn Mendeleev, hay ngắn gọn bảng tuần hoàn, là một phương pháp liệt kê các nguyên tố hóa học thành bảng, dựa trên số hiệu nguyên tử (số proton trong hạt nhân), cấu hình electron và các tính chất hóa học tuần hoàn của chúng. Các nguyên tố được biểu diễn theo trật tự số hiệu nguyên tử tăng dần, thường liệt kê cùng với ký hiệu hóa học trong mỗi ô. Dạng tiêu chuẩn của bảng gồm các nguyên tố được sắp xếp thành 18 cột và 7 dòng, với hai dòng kép nằm riêng nằm bên dưới cùng.

Hok tốt .

# MissyGirl #

Hệ tuần hoàn là hệ cơ quan có chức năng tuần hoàn máu trong cơ thể của hầu hết các động vật. Hệ tuần hoàn vận chuyển chất dinh dưỡng, ôxy, cacbon điôxít, hormone, tế bào máu ra và vào các tế bào trong cơ thể để nuôi dưỡng nó và giúp chống lại bệnh tật, ổn định nhiệt độ cơ thể và độ pH, và để duy trì cân bằng nội môi.

15 tháng 12 2021

Thư gửi ông già Noel bằng tiếng Anh 

Dear Santa Claus,

My name is Sally and I am 5 and 1/2 years old. I have been a very good girl this year. I help Mommy wash the dishes every night, and I listen to Daddy when he tells me to clean my room. I am also nice to my little brother, even though he can be really annoying sometimes.

Thank you for all the presents last year. They were all really nice, and I played with all of them a lot. This year I would a jump rope, a kitten, and a new bike. I really really want the bike.

Please give my love to Mrs. Claus, the elves, and all the reindeer, especially Rudolph. I will leave some carrots for the reindeer next to your milk and cookies.

Love,

Sally

15 tháng 12 2021

Dear Santa,

My name is Khanh Ngoc . I am 14 years old, I am living in Vietnam.

How have you been, elves and Mrs Claus been?

This year, I have been a good child. I am always nice to my sister, brother and friends. I always do my homework and help my parents by cleaning my rooms and put all of my toys back to their place. I wish to have a smartphone this Christmas because my smartphone is broken.

Thank you, Santa, for bringing so much joy to kids me gifts every year. See you on twenty-four of December. Thank you very much

Merry Christmas!

Love,

LÀM , NÊU LÝ THUYẾT TỪNG CÂU VÀ DỊCH NGHĨA GIÚP MÌNH LUÔN NHA GẤP LẮM RỒI ~IV. Make sentences using the given words.1. If/people/ not/ stop/ dumping/ waste/ into/ rivers/,/pollution/ increase/.___________________________________________________________2. If/ polar/ ice caps/ melt/ ,/huge landmasses/ be/ under/ water._____________________________________________________________3. If the air/ in/ city/ be/polluted/ ,it/can/ cause/ people’s/ respiratory/...
Đọc tiếp

LÀM , NÊU LÝ THUYẾT TỪNG CÂU VÀ DỊCH NGHĨA GIÚP MÌNH LUÔN NHA GẤP LẮM RỒI ~

IV. Make sentences using the given words.

1. If/people/ not/ stop/ dumping/ waste/ into/ rivers/,/pollution/ increase/.

___________________________________________________________

2. If/ polar/ ice caps/ melt/ ,/huge landmasses/ be/ under/ water.

_____________________________________________________________

3. If the air/ in/ city/ be/polluted/ ,it/can/ cause/ people’s/ respiratory/ problems.

_________________________________________________________

4. If/smog/ be/ frequently/ formed/ in/ city/,/it/ cause/ difficulty/ in/ breathing/ headache/ even/ lung cancer.

___________________________________________________

5. If/ carbon monoxide/ concentrate/ in/ great/ amounts/, /it/ be/ harmful/.

___________________________________________________________

6. The climate/ change/ if/ more trees/ be/ cut/ down/ for/ hardwood/.

_____________________________________________________________

7. If/ we/ not/ control/ pollution/ soon/,/it/ be/ too/ late/.

_____________________________________________________________

8. If/we/ not/ protect/ frontier/,/we/ suffer/ many/ from/ natural/ disasters.

______________________________________________________________

1

1, If people do not stop dumping waste into rivers, the pollution will increase.

2,If the polar ice caps melt , huge landmasses will be under water.

3, If the air in city is polluted, it can cause peole's respiratory problems.

4,If smog is frequently formed in the city, it will cause dificulty in breathing, headache and even lung cancer,

5, If carbon monoxide concentrates in great amounts , it will be harmful.

6, The climate will change if more trees are cut down for hardwood.

7, If we do not control the pollution soon , it will be too late.

8, If we do not protect the frontier, we will suffer from many natural disasters.

@tired

5 tháng 1 2022

bạn nêu lý thuyết từng câu rồi mình bấm đúng nha

22 tháng 11 2019
  1. Do you know anything about Math ?
  2. What is the meaning of triangle ?

.............. Cái này lấy cũng khá dễ nha bạn !

18 tháng 4 2019

Bạn ko phải là tách trà của tôi. Nếu sai thì bn có thể vào Google dịch nhé!!

18 tháng 4 2019

Bạn không phải là trà của tôi

9 tháng 12 2021

1B

2B

3B

4A

5A

1B

2C

3A

4B

10 tháng 12 2021

Đang thi tự làm

27 tháng 7 2016

Life in the city is full of activity. Early in the morning hundreds of people rush out of their homes in the manner ants do when their nest is broken. Soon the streets are full of traffic. Shops and offices open, students flock to their schools and the day's work begins. The city now throb with activity, and it is full of noise. Hundreds of sight-seers, tourists and others visit many places of interest in the city while businessmen from various parts of the world arrive to transact business.
Then towards evening, the offices and day schools begin to close. Many of the shops too close. There is now a rush for buses and other means of transport. Everyone seems to be in a hurry to reach home. As a result of this rush, many accidents occur. One who has not been to the city before finds it hard to move about at this time. Soon, however, there is almost no activity in several parts of the city. These parts are usually the business centres.
With the coming of night, another kind of actịvity begins. The streets are now full of colorful lights. The air is cooler and life becomes more leisurely. People now seek entertainment. Many visit the cinemas, parks and clubs, while others remain indoors to watch television or listen to the radio. Some visit friends and relatives and some spend their time reading books and magazines. Those who are interested in politics discuss the latest political developments. At the same time, hundreds of crimes are committed. Thieves and robbers who wait for the coming of night become active, and misfortune descends upon many. For the greed of a few, many are killed, and some live in constant fear. To bring criminals to justice, the officers of the law are always on the move.
Workers and others who seek advancement in their careers attend educational institutions which are open till late in the night. Hundreds of them sit for various examinations every year. The facilities and opportunities that the people in the city have to further their studies and increase their knowledge of human affairs are indeed many. As a result, the people of the city are usually better informed than those of the village, where even a newspaper is sometimes difficult to get.
The city could, therefore, be described as a place of ceaseless activity. Here, the drama of life is enacted every day

Chúc bn học tốt

27 tháng 7 2016

The village has always been known to be a place of peace and quiet. The scattered houses among hundreds of plants and trees at once indicate the lack of activity in the village. 

The workers in the village leave their homes early in the morning to work in the plantations or towns nearby. Some have their own plantations, and some make certain articles in their homes to sell them in the towns. A few of the villagers, including women, go out to catch fish in the streams and rivers found in the village. Though the people of the village do not usually earn much, yet they seem to be contented. 

In the afternoon, most of the villagers are at home. Some of them take a nap after lunch; some work in their small gardens, and some visit the small shops in the village. In various parts of the village children may be seen playing the popular games of the village. Occasionally, a cyclist passes by. 

Then, in the evening, the villagers meet one another. Some play cards and other types of games peculiar to the village. Some talk about the day's incidents in the village, and those whose minds go beyond the village discuss world events. 

In almost every village there is a headman whose duty is to settle quarrels among the villagers and maintain peace in the village. Whenever there is a dispute, the villagers go to the headman who is held in such esteem that his word has the force or law. In this way the villagers have developed their own simple laws, and the crimes of cities are almost unknown to the people of the village. 

During a festival, the whole village is alive with activities. Everyone is in a happy mood and plays his part to make the festival a success. This is the time for the men, women and children of the village to wear their best clothes and the village is full of colour. These simple ways of life in the village, however, must soon change. Progress in science and education has already begun to affect the outlook of the people in the village, and hundreds are leaving the village to seek their fortunes in the towns and cities. 

Chúc bạn học tốt