Dựa vào tiêu chí nào để phân chia vỏ Trái Đất thành vỏ lục địa và vỏ đại dương?

Phản ứng giữa bromate ion và bromine ion trong dung dịch acid:

\(\text{BrO}_{3}^{-}+5\text{B}{{\text{r}}^{-}}+6{{\text{H}}^{+}}\to 3\text{B}{{\text{r}}_{2}}+3{{\text{H}}_{2}}\text{O}\) 

Sau một khoảng thời gian, đo được: \(-\frac{\Delta {{C}_{B{{r}^{-}}}}}{\Delta t}=2,{{0.10}^{-3}}\left( \text{M}~{{\text{s}}^{-1}} \right)\) 

Vậy tốc độ trung bình của phản ứng trong khoảng thời gian đó là

Choose A, B, C or D to answer the question.

You are in a study group where some classmates are already working on a challenging homework assignment. You haven’t started yet and feel a bit nervous to ask for help, but you want to join them. What can you say to participate in the group homework session?

To children, family plays a role in ____.

Nêu các phương pháp nghiên cứu thường được sử dụng trong Vật lí?

Phương trình \(\sqrt {{x^2} + 2x - 3} = 5 - x\) có nghiệm là \(x = \frac{a}{b}\). Khi đó \(a + 2b\) bằng?

Vì sao quân đội triều đình nhanh chóng thất thủ tại thành Hà Nội năm 1873?

Gọi S là tập giá trị của tham số m để giá trị nhỏ nhất của hàm số $f\left(x\right)=\left|x^2-4x+m\right|$ trên đoạn $\left[1 ; 4\right]$ bằng 6. Tổng các phần tử của S bằng?

Read the passage carefully. Choose an option (A, B, C or D) that best answers each question from 23 to 30.

1. How do children learn about wildlife? And is what they learn the sort of thing they should be learning? It is my belief that children should not just be acquiring knowledge of animals but also developing attitudes and feelings towards them based on exposure to the real lives of animals in their natural habitats. But is this happening?

2. Some research in this area indicates that it is not. Learning about animals in school is often completely disconnected from the real lives of real animals, with the result that children often end up with little or no understanding or lasting knowledge of them. They learn factual information about animals, aimed at enabling them to identify them and have various abstract ideas about them, but that is the extent of their learning. Children's storybooks tend to personify animals as characters rather than teach about them.

3. For direct contact with wild and international animals, the only opportunity most children have is visiting a zoo. The educational benefit of this for children is often given as the main reason for doing it but research has shown that zoo visits seldom add to children's knowledge of animals – the animals are simply like exhibits in a museum that the children look at without engaging with them as living creatures. Children who belong to wildlife or environmental organizations or who watch wildlife TV programmes, however, show significantly higher knowledge than any other group of children studied in research. The studies show that if children learn about animals in their natural habitats, particularly through wildlife-based activities, they know more about them than they do as a result of visiting zoos or learning about them in the classroom.

4. Research has also been done into the attitudes of children towards animals. It shows that in general terms, children form strong attachments to individual animals, usually their pets, but do not have strong feelings for animals in general. This attitude is the norm regardless of the amount or kind of learning about animals they have at school. However, those children who watch television wildlife programs show an interest in and affection for wildlife in its natural environment, and their regard for animals in general is higher.

What can be inferred from paragraph 4 about children's attitudes to animals?

Theo quy định pháp luật, công dân có thể thực hiện quyền tố cáo trong tình huống nào sau đây?

“Thống nhất hoàn toàn hay là chết” là khẩu hiệu thể hiện tư tưởng nào sau đây?

Đơn vị của cường độ điện trường là

Số hiệu nguyên tử cho biết thông tin nào sau đây?

Read the following passage about the impact of tweeting on everybody and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22

EVERYBODY’S TWEETING

Twitter (18) ________________ for a podcasting website, but then people realized that it offered them the power to connect with millions of people instantly. Suddenly, everyone had a voice, as long as it wasn’t longer than 140 characters. But what are we using it for, and just how is Twitter changing the way we do things?

Perhaps the greatest impact Twitter has had is on breaking news. Before Twitter, (19) _____________ before finally broadcasting it on the radio or TV. These days, anyone who happens to be in the right place at the right time with a Twitter account can post news the second it happens. For example, Janis Krums posted a photo and a tweet when he witnessed a US flight making an emergency landing in the Hudson River. He must never have imagined that he would break the story to the world.

Following Pop Idols

Young people have always loved to follow their pop idols, and Twitter has made it a whole lot easier. Before the Internet, teenagers used to join the fan clubs of their favorite bands and write letters to their heroes,

(20) _________________ to get a reply written by the club secretary. Today’s teenagers don’t need to wait. By following their idols on Twitter, they get all the news the minute it happens: their meals, activities, or even thoughts. And all the news comes directly from the bands themselves.

Creating Movements

Twitter allows people who think the same way to get together and (21) ______________. These problems may be cyberbullying, sexism, or racism. They can share information, organize campaigns, and put pressure on related departments. Twitter has given the man and woman on the street the power to make a difference.

Identifying the source of a piece of news

It’s good to get an idea of the background of a person who says or writes something. Are they an impartial expert or someone who wants to change your opinion to suit their own agenda? For example, this statement about a flu epidemic, “Patients can already spread the virus a day before they’ve even fallen sick themselves”, is more likely to come from a doctor than a politician. On the other hand, “We have to stop people who are carrying the virus from getting into the country” is more likely to come from a politician. (22) _____________, you’re better able to decide how much importance to give it and whether you can really trust what they say.

Kinh doanh là việc thực hiện liên tục một, một số hoặc tất cả công đoạn của quá trình từ đầu tư, sản xuất, tiêu thụ sản phẩm hoặc cung ứng dịch vụ trên thị trường nhằm mục đích nào sau đây?

Bốn phát minh quan trọng về kĩ thuật của người Trung Quốc thời kì cổ - trung đại là:

Phương pháp kí hiệu dùng để thể hiện các đối tượng nào?

Đun một lượng nước tới nhiệt độ sôi, dưới áp suất khí quyển trong một chiếc ấm. Cho nhiệt hóa hơi riêng của nước là 2,3.10⁶ J/kg. Nhiệt lượng cần thiết để có 100 g nước hóa thành hơi là

Cho đường thẳng \(d: \frac{x}{1}=\frac{y-1}{2}=\frac{z+1}{-1}\) và điểm \(A(1 ; 2 ;-3)\). Phương trình mặt cầu đi qua \(A\) và có tâm là giao điểm \(d\) với \((O x y)\) có dạng: \((x-a)^{2}+(y-b)^{2}+(z-c)^{2}=d\). Tổng \(a+b+c+d\) bằng bao nhiêu?

Cho phương trình lượng giác \(3-\sqrt{3}\text{tan}\left( 2x-\frac{\pi }{3} \right)=0\).

Cho các phát biểu sau:

(1) Các tế bào là đơn vị cơ sở của cơ thể sống.

(2) Các tế bào có thành phần hóa học tương tự nhau.

(3) Tất cả các tế bào có vật chất di truyền là RNA.

(4) Hoạt động sống của tế bào là sự phối hợp hoạt động của các nguyên tử trong tế bào.

Số phát biểu đúng theo quan điểm của học thuyết tế bào là