Cho 3,09 gam muối natri halogenua (X) tác dụng với dung dịch A g N O 3   dư thì thu được một kết tủa, kết tủa này sau khi phân hủy hoàn toàn cho 3,24 gam bạc. Công thức của muối X là

A. NaF

B. NaBr

C. NaI

D. NaCl

The Old Man and the Sea is a short novel written by the American author Ernest Hemingway in 1951 in Bimini, Bahamas, and published in 1952. It was the last major work of fiction by Hemingway that was published during his lifetime. One of his most famous works, it tells the story of Santiago, an aging Cuban fisherman who struggles with a giant marlin far out in the Gulf Stream off the coast of Florida.

    In 1953, The Old Man and the Sea was awarded the Pulitzer Prize for Fiction, and it was cited by the Nobel Committee as contributing to their awarding of the Nobel Prize in Literature to Hemingway in 1954.

 What genre does The Old Man and the Sea belong to?

A. fiction

B. fairy tale

C. humour

Chọn câu sai.

A. Các đường mạt sắt của từ phổ cho biết dạng các đường sức từ

B. Các đường sức của từ trường đều cỏ thế là các đường cong cách đều nhau

C. Nói chung các đường sức điện thì không kín, còn các đường sức từ là các đường cong kín

D. Một hạt mang điện chuyển

Trình bày quá trình hình thành phoi

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

         Educating children at home as an alternative to formal education is an option chosen by families in many parts of the world. The homeschooling movement is popular in the United States, where close to one million Children are educated at home. In Canada, 1 percent of school-age children are homeschooled, and the idea also enjoys growing popularity in Australia, where 20,000 families homeschool their children. The movement is not limited to these countries. Homeschooling families can be found all over the world, from Japan to Taiwan to Argentina to South Africa.

         Homeschooling is not a novel idea. In fact, the idea of sending children to spend most of their day away from home at a formal school is a relatively new custom. In the United States, for example, it was not until the latter part of the nineteenth century that state governments began making school attendance compulsory. Before that, the concept of a formal education was not so widespread. Children learned the skills they would need for adult life at home from tutors or their parents, through formal instruction or by working side by side with the adults of the family.

         In the modern developed world, where the vast majority of children attend school, families choose homeschooling for a variety of reasons. For people who live in remote areas, such as the Australian outback or the Alaskan Wilderness, homeschooling may be their only option. Children who have exceptional talents in the arts or other areas may be homeschooled so that they have more time to devote to their special interests. Much of the homeschooling movement is made up of families who, for various reasons, are dissatisfied with the schools available to them. They may have a differing educational philosophy, they may be concerned about the safety of the school environment, or they may feel that the local schools cannot adequately address their children's educational needs. Although most families continue to choose a traditional classroom education for their children, homeschooling as an alternative educational option is becoming more popular.

What does the author mean in the last sentence?

A. Families are gradually aware of the importance of school attendance.

B. More and more parents choose homeschooling to educate their children.

C. Homeschooling will replace the traditional classroom one day in the future

D. Many people prefer formal schools because of its fame.