Chứng minh rằng với mọi a, b, c ta luôn có:

( a   +   b   +   c ) 3   =   a 3   +   b 3   +   c 3  + 3(a + b)(b + c)(c + a).

Cho hai đường thẳng a và b song song với nhau, cách nhau 1 một khoảng là h. Một đường tròn (O) tiếp xúc với a và b. Hỏi tâm O di động trên đường nào?

Thực hiện phép tính:

a) (-12).4;

b) (-11).5;

c) 25. ( -2);

d) 10. (- 4).

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part is pronounced differently from that of others in each of the following questions.

A. preface

B. gazelle

C. surface

D. flamingo

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 3 to 7.

Back in the 1960s and 1970s, the world was becoming more aware of the destructive effects of industry (3)_____ the environment and people were starting to think seriously about ways of protecting the environment. One man who was particularly affected by this subject was Gerard Morgan-Grenville. As Morgan-Grenville travelled round earning his living as a gardener, he noticed signs of the damage that was being done to the countryside around him. It wasn't long before Morgan-Grenville decided that he had to do something about this situation. He felt that if people could be shown a better way of living then maybe they would be interested enough to try to protect their (4)_____ environment.

Mr. Morgan-Grenville decided to set up a project (5) ______ would prove what was happening to our surroundings and what could be done about it. So, in 1975, Morgan-Grenville created the Centre for Alternative Technology (CAT) in a village in Wales.

The main aim of CAT is to search for an ecologically better way of living by using technology which (6) _____ no harm to the environment. One of the most important things CAT did initially was to explore and demonstrate a wide range of techniques and to point out which ones had the least destructive results on the world around us. (7)____, CAT provides information and advice to people all over Britain and all over the world. If more and more individuals are informed about how much damage our modern lifestyle is causing to the planet, maybe more of them would be prepared to look for practical solutions to environmental problems.

Điền vào ô 6.

A. gets

B. makes

C. plays

D. does