tại sao nước cua khi đun ở nhiệt độ 100 độ c thì có các mảng hiện lên?

so sánh pđ biện chứng và pđ siêu hình? cho vd?

Có mấy dấu câu trong tiếng việt? Nêu ý nghĩa của mỗi dấu câu?

Làm ơn giúp mình vs

Chọn số liệu thích hợp để điền vào chỗ trống trong câu sau : Da người thải khoảng ... các sản phẩm bài tiết hoà tan trong máu (trừ C O 2 ).

A. 30%

B. 5%

C. 10%

D. 20%

Khi đehiđrat hóa ancol X, sản phẩm chính là 2-metylpent-2-en. Vậy X không thể là

A. Ancol bậc I

B. Ancol bậc II

C. Ancol bậc III

D. 2-metylpentan-2-ol

Khi nói về sự khác nhau ADN trong và ngoài nhân ở tế bào nhân thực có các phát biểu sau:

(1) ADN trong nhân có cấu trúc xoắn kép dạng sợi còn ADN ngoài nhân có cấu trúc kép dạng vòng.

(2) ADN trong nhân có số lượng nuclêôtit lớn hơn so với ADN ngoài nhân.

(3) ADN ngoài nhân nhân đôi độc lập so với ADN trong nhân.

(4) ADN ngoài nhân có cấu trúc xoắn kép dạng sợi còn ADN trong nhân có cấu trúc kép dạng vòng.

Số phát biểu có nội dung đúng là:

A. 3.

B. 2.

C. 4.

D. 1.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the question.

          Life expectancy is the period of time that a person can expect to live. Life expectancy varies greatly between genders and cultures. It used to be that women had a lower life expectancy than men (1 in every 4 women died in childbirth), but now they live an average of four to five years longer than men. Life expectancy has been increasing rapidly over the last centuries. With the advent of such modern miracles as sewers, medicine and a greater understanding of how diseases are spread, our life expectancy has increased by 25 – 30 years.

          In developing countries like Swaziland, where there is a high HIV/AIDS rate, life expectancy is as low as 32,6 years. In developed countries like Australia, life expectancy rates as high as 81 years. There are an increasing number of factors which can cancel out the disadvantages you have. The one that we are looking at now is how your career can affect your life expectancy. Choosing the wrong career can result in a shorter life!

          If you want your career to positively influence your life expectancy, you have to be made of money. That’s right. Rich people in wealthy areas of England and France live 10 years longer than the people in poorer areas. Having a successful career has its drawbacks, too if the result of hard work its stress.

          Stress can lead to a number of psychological disorders such as depression, anxiety, fatigue, tension and aggression. These conditions may result in a lack of concentration and an increase in serious injuries at work. They can also lead to high blood pressure and heart attacks which seriously affect life expectancy.

          If you are worried that your job might decrease your  life expectancy, you probably need to avoid careers on “dangerous jobs” list such as timber cutters, pilots, construction workers, roofer, truck drivers.

          So if you don’t want to kick the bucket at an early age, choose a career in something other than timber cutting, but above all, remember to relax.

From Pre-Essence Reading by Rachel Lee, Longman

What is the main idea of the 1^st paragraph?

A. Stress negatively affects life expectancy 

B. Making a bad career choice will make your life shorter 

C. Life expectancy has increased greatly over the last few centuries 

D. Stress results in lower life expectancy

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the question.

          Life expectancy is the period of time that a person can expect to live. Life expectancy varies greatly between genders and cultures. It used to be that women had a lower life expectancy than men (1 in every 4 women died in childbirth), but now they live an average of four to five years longer than men. Life expectancy has been increasing rapidly over the last centuries. With the advent of such modern miracles as sewers, medicine and a greater understanding of how diseases are spread, our life expectancy has increased by 25 – 30 years.

          In developing countries like Swaziland, where there is a high HIV/AIDS rate, life expectancy is as low as 32,6 years. In developed countries like Australia, life expectancy rates as high as 81 years. There are an increasing number of factors which can cancel out the disadvantages you have. The one that we are looking at now is how your career can affect your life expectancy. Choosing the wrong career can result in a shorter life!

          If you want your career to positively influence your life expectancy, you have to be made of money. That’s right. Rich people in wealthy areas of England and France live 10 years longer than the people in poorer areas. Having a successful career has its drawbacks, too if the result of hard work its stress.

          Stress can lead to a number of psychological disorders such as depression, anxiety, fatigue, tension and aggression. These conditions may result in a lack of concentration and an increase in serious injuries at work. They can also lead to high blood pressure and heart attacks which seriously affect life expectancy.

          If you are worried that your job might decrease your  life expectancy, you probably need to avoid careers on “dangerous jobs” list such as timber cutters, pilots, construction workers, roofer, truck drivers.

          So if you don’t want to kick the bucket at an early age, choose a career in something other than timber cutting, but above all, remember to relax.

From Pre-Essence Reading by Rachel Lee, Longman

According to the passage, which of following is true if you have a successful career?

A. You can buy an expensive car

B. Your life expectancy increases by a decade 

C. You can afford to exercise and eat well

D. You can spend most of your day in an office

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer for each of the questions.

Throughout the world there are different ways for people to greet each other. In much of the world, a handshake is the (38) __________ form of welcoming and greeting someone. In many countries around the Mediterranean Sea a (39) ___________ kiss on the cheek is the appropriate way to welcome friends and family. It can be a very (40) __________ surprise if you expect to shake hands and get a kiss or a hug instead. 

At times, it is difficult to tell what sort of greeting (41) ___________ is followed. People may bow, grab another’s arm or even slap the other person on the back. In some places people just smile, look at the other’s face and say nothing. 

Most people in the world are tolerant of visitors and don’t mind what travellers do that seems wrong as long as the visitors are (42)__________. A big part of the delightfulness of world travel is experiencing different customs

Điền ô số 41

A. habit

B. routine

C. custom

D. tradition

Dãy các kim loại được xếp theo chiều giảm dần tính khử là

A. Cu, K, Fe.

B. K, Cu, Fe.

C. Fe, Cu, K.

D. K, Fe, Cu.