Bài 4. Cho tam giác ABC, M là trung điểm của BC. Trên nửa mặt phẳng không chứa C có bờ AB, vẽ tia Ax vuông góc với AB, trên tia đó lấy D sao cho AD=AB. Trên nửa mặt phẳng không chứa B có bờ AC, vẽ tia Ay vuông góc với AC, trên tia đó lấy E sao cho AE=AC

Chứng minh rằng

a )AM=1/2DE

b)AM vuông góc với DE nhớ vẽ hình

Bài 4. Cho tam giác ABC, M là trung điểm của BC. Trên nửa mặt phẳng không chứa C có bờ AB, vẽ tia Ax vuông góc với AB, trên tia đó lấy D sao cho AD=AB. Trên nửa mặt phẳng không chứa B có bờ AC, vẽ tia Ay vuông góc với AC, trên tia đó lấy E sao cho AE=AC

Chứng minh rằng

a )AM=1/2DE

b)AM vuông góc với DE

Bài 3. Cho tam giác ABC có góc BAC = a(0 độ < a <180 độ) , hai đường phân giác của góc B, C cắt nhau tại T. Tính góc BTC theo a. Tìm a biết góc BTC=2BAC

C

III. Give the correct forms of the verbs in brackets.

1. If you ( go) __________away, please write to me.

2. If you (see) __________Mary today, please (ask) __________her to call me.

3. If he (eat) __________another cake, he will be sick.

4. If he (take) __________my advice, everything can go well.

5. What you (do) __________if she refuses your invitation?

6. Unless they (pass) __________their examinations, they would join the army.

7. You (be) __________ill if you drink that water.

8. If it’s raining heavily, we (not go) __________for a donkey ride.

9. If he (try)__________ hard, he’ll pass the examination.

10. If I (finish) __________the work in time, I (go)__________ to the football game.

11. If the weather stays good next weekend, we………… (probably / go ) away somewhere.

12. Come on! If we (hurry)…………………….,we ( catch )……………….. the bus.

13. There (be)…………………big floods every year if the cutting down of trees continues.

14. If there (be) ……………….too much litter on the streets, the environment will become polluted.

15. If the sea level (rise)…………………, there will be floods in many parts of the world.

16. They will be late for their meeting if they ( not leave )…………………………now.

17. If you aren’t careful, you (drop)…………………………..the plates.

18. If anyone (phone)…………………………. me , tell them I’m out.

19. If he ( not use)……………………much pesticide on vegetables, they will become edible.

20. What (you/ do) ............................... if you are free tomorrow, Lan?

21. If I ............................. (study), I.....................................................(pass) the exams.

22 If the sun........................... ( shine), we ........................ (walk) to the town.

23. If he ............................. ( have) a temperature, he ............................ ( see) the doctor.

24. If my friends .............................( come), I .....................................( be) very happy.

25. If she.........................( earn) a lot of money, she ..............................( fly) to New York.

26. If we .......................( travel) to London, we .................................( visit) the museums.

27. If you .............. ( wear) sandals in the mountains, you......................( slip) on the rocks.

28. If Rita ............. (forget) her homework, the teacher....................(give) her a bad mark.

29. If they...........................(go) to the disco, they ..............................(listen) to loud music.

30. If you .............................(wait) a minute, I............................(ask) my parents.

II. Choose the correct answer.

1. My brother likes watching TV, _______ I like going out with my friends.

         A. and                            B. or                            C. so                           D. but 

2. Nam likes _______ weather because he can go swimming.

       A. hot                               B. cold                        C. rainy                       D. windy

3. ........... talk in class.

       A. Do                               B. Don’t                      C. Does                      D. Aren’t

4. As it doesn’t snow in Viet Nam, we can not ________ skiing.

       A. play                             B. do                           C. watch                     D. go

5. I .............Ha Noi three times.

       A. visited                         B. has visited             C. have visited           D. visit

6. Pele is the ……………… player of all time.

A. well-known                  B. famous                    C. popular                   D. greatest

8. Pele is the most ……………… player of all time.

A. well-known                  B. strongest                 C. happiest                  D. greatest

9. The most famous building in ……….. is Eiffel Tower.

A. Paris                             B. London                   C. New York               D. Melbourne

10. Tet is the ………………… holiday in Viet Nam

A. interesting                    B. expensive               C. relaxing                  D. most colorful

11. The …………… I like best is Xuan Bac.

A. comedy                  B.  comedian               C.  fun                         D.  funny

12. I …………………..to Australia many times.

A. visited                    B. have been               C. go                           D. went

13. I ……………. to the cinema with my friends last night.

A. go                           B. went                        C. have gone               D. going

14. My brother can swim well …………….. he also can play volleyball.

A. so                            B. because                   C. but                          D. and

15.…………… eat too much salt. It’s not good for your health.

A. Do                          B. please                     C. Don’t                      D. Can’t

16.…………… fine weather!

A. What                      B. How                        C. It                             D. Which

17. The house will be in the mountain, .........................by many tall old trees.

A. surround                 B. surrounding            C. surrounded D. surrounds

18...............................can wash and dry dishes.

A. a washing machine B. a modern fridge      C. a dishwasher          D. a robot

19. Will you have a robot that can ...............your children?

A. look after                B. take care of             C. watch                      D. see

20. Phong is thinking .....................what he will do on Sunday?

A. of                            B. at                            C. about                      D. for