Khi nhỏ từ từ đến dư dung dịch NaOH vào dung dịch hỗn hợp gồm AlCl3 và FeCl3, kết quả thí nghiệm được biểu diễn trên đồ thị sau:

 

Khi x=0,66 thì giá trị của m (gam) là?             

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 questions:

                                                        ACADEMICS AREN’T THE PROBLEM

Studies about how students use their time might shed light on whether they face increased academic and financial pressures compared with earlier eras.

Based on data about how students are spending time, academic or financial pressures don’t seem to be greater now than a generation ago.

The data show that full-time students in all types of colleges study much less now than they did a generation ago - a full 10 hours a week less. Students are also receiving significantly higher grades. So it appears that academic pressures are, in fact, considerably lower than they used to be.

The time-use data don’t suggest that students feel greater financial pressures, either. When the time savings and lower opportunity costs are factored in, college appears less expensive for most students than it was in the 1960s. And though there are now full-time students working to pay while in college, they study less even when paid work choices are held constantly.

In other words, full-time students do not appear to be studying less in order to work more. They appear to be studying less and spending the extra time on leisure activities or fun. It seems hard to imagine that students feeling increased financial pressures would respond by taking more leisure.
   

Based on how students are spending their time then, it doesn’t look as though academic or financial pressures are greater now than a generation ago. The time-use data don’t speak directly to social pressures, and it may well be that these have become more intense lately.

In one recent set of data, students reported spending more than 23 hours per week either socializing with friends or playing on the computer for fun. Social activities, in person or on computer, would seem to have become the major focus of campus life. It is hard to tell what kinds of pressures would be associated with this change.

Question: Students nowadays seem to be studying less and _______.             

Tìm hệ số của trong khai triển .  

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

The biologist's role in society as well as his moral and ethical responsibility in the discovery and development of new ideas has led to a reassessment of his social and scientific value systems. A scientist can no longer ignore the consequences of his discoveries; he is as concerned with the possible misuses of his findings as he is with the basic research in which he is involved. This emerging social and political role of the biologist and all other scientists requires a weighing of values that cannot be done with the accuracy or the objectivity of a laboratory balance. As a member of society, it is necessary for a biologist now to redefine his social obligations and his functions, particularly in the realm of making judgments about such ethical problems as man's control of his environment or his manipulation of genes to direct further evolutionary development.

Probably the greatest biological problem of the future, as it is of the present, will be to find ways to curb environmental pollution without interfering with man's constant effort to improve the quality of his life. Many scientists believe that underlying the spectre of pollution is the problem of surplus human population. A rise in population necessitates an increase in the operations of modern industry, the waste products of which increase the pollution of air, water, and soil. The question of how many people the resources of the Earth can support is one of critical importance.

Question: What is probably the most important biological problem mentioned in the passage?         

Tổng bằng:  

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

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains, mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

 Question 37: According to the passage, the difficulty in diagnosing allergies to foods is due to ______________.  

Để thu được kết quả  ta phải khai triển biểuthức nào sau đây?         

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

The American type of football was developed in the 19th century from soccer and rugby football. Played by professionals, amateurs, college and high school students, or young children, football in American is one of the most popular sports besides basketball and baseball. It attracts millions of fans each fall and people are very supportive of their favourite teams. The football playing field of today is rectangular in shape and measures 100 yards long and 53.5 yards wide. White lines are painted on the playing field to mark off the distances to the end zone. The games is divided into four quarters, each fifteen minutes long. The first two quarters are known as the first half. There is a rest period between two halves which usually last about fifteen minutes. Each team has eleven players. Each team has offensive players who play when the team has possession of the ball and defensive players who play when the other team has the possession of the ball. Because of the body contact players have during the game, helmets are worn to protect their head and face area, whereas pads are worn to protect the shoulders, arms, and legs. Also, there are officials carrying whistles and flags to make certain that  the rules of the game are followed during the game. The football is made of leather and is brown in colour. It is shaped much like an oval and has white rings near each end of the football. These rings help the players see the ball when it is thrown or someone is running with it. The eight stitches on the top of the football help the  players to grip the ball when throwing or passing. The most famous game of the year is Super Bowl that is played in January or February. It is televised around the world and is watched by millions of people each year.

Question: When is the most famous football game held annually?         

Một dãy ghế dài có ghế. Xếp một cặp vợ chồng ngồi vào trong ghế sao cho người vợ ngồi bên phải người chồng (không bắt buộc phải ngồi gần nhau). Số cách xếp là:

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

The American type of football was developed in the 19th century from soccer and rugby football. Played by professionals, amateurs, college and high school students, or young children, football in American is one of the most popular sports besides basketball and baseball. It attracts millions of fans each fall and people are very supportive of their favourite teams. The football playing field of today is rectangular in shape and measures 100 yards long and 53.5 yards wide. White lines are painted on the playing field to mark off the distances to the end zone. The games is divided into four quarters, each fifteen minutes long. The first two quarters are known as the first half. There is a rest period between two halves which usually last about fifteen minutes. Each team has eleven players. Each team has offensive players who play when the team has possession of the ball and defensive players who play when the other team has the possession of the ball. Because of the body contact players have during the game, helmets are worn to protect their head and face area, whereas pads are worn to protect the shoulders, arms, and legs. Also, there are officials carrying whistles and flags to make certain that  the rules of the game are followed during the game. The football is made of leather and is brown in colour. It is shaped much like an oval and has white rings near each end of the football. These rings help the players see the ball when it is thrown or someone is running with it. The eight stitches on the top of the football help the  players to grip the ball when throwing or passing. The most famous game of the year is Super Bowl that is played in January or February. It is televised around the world and is watched by millions of people each year.

Question: Why are there white rings on each end of the football?         

Xếp người (trong đó có một cặp vợ chồng) ngồi quanh bàn tròn có cái ghế không ghi số sao cho cặp vợ chồng ngồi cạnh nhau. Số cách xếp là: