Bài gì vậy bạn 

1 tom won't be late , will he?

2 you look tired, don't you ?

3 lan came in her sport car, didn't she ?

4 let's go out tonight, shall we ?

5 you couldn't do me a favor , could you ?

6 minh has seen hoa today , hasn't he ?

7 there aren't  many people at the meeting , are there ?

8 i'm too impatient , aren't I ?

9 lien doesn't know you , does she ?

10 these cakes look good, aren't these ?

11 you can speak german , can't you ?

12 don't drop that that vase , will you ?

13your mother is on holiday, isn't she ?

14people use the internet for many purposes, don't they  ?

?

cái này rút gọn thôi

2xS=2^1+2^2+...+2^64

2S-S=2^64-1

S=2^64-1

nhớ bấm đúng nhé

                                              Giải

 S = 1+2+2^2+2^3+...+2^62+2^63       (1)      

  Nhân hai vế với 2 ta có :   

2S = 2+2^2+^3+...+2^63+2^64            (2)

Trừ từng vế đắng thức (2) cho đẳng thức (1), ta có : S = 2^64-1         

1. Igor Sikorsky invented the first helicopter in the world.

A. True              B. False              C. Not mentioned

2. Who created the word "helicopter"?

3. Why was Igor Sikorsky called the father of helicopter?

4. Igor Sikorsky designed VS-300 helicopter model _____?

5. What made Igor Sikorsky's helicopters successful?

6. On the whole, the passage is about _____.

1. What time does the library close?

  - It closes ……at……about half ……past……four.

2. Can you help me wash ……up……these dirty glasses?

3. We look ……up…………..the new words in the dictionary.

4. You shouldn’t eat and watch TV …at…….the same time.

5. These cards are in alphabetical order and ……by……author.

6. Schools in Vietnam are different …from…….those in the USA.

7. What is your date ……of…birth?

- November eighth.

8. Farmers are very hard-working. They work from morning ……till…night on their farms.

9. I like to live ……in….the countryside because people there are more friendly.

10. Mr. Minh is not at home now. He is …at………work.

+ I am upstairs. I (have) am having a bath.

1. We always need more players. Why don’t you come ………………?

A. on                                    B. along                        C. with                         D. after

2. Will you be home …………..dinner tonight?

A. to                                    B. for                           C. at                             D. on

3. Giving a book report before the class is an interesting …………………..

A. act                                   B. action                       C. activity                     D. deed

4. Do you go out ………..?

A. in the afternoon on Fridays                                   B. on Fridays  in the afternoon

C. on afternoons Friday                                            D. on Friday afternoons

5. …………….lives in a very big house

A. A Queen of England                                             B. Queen of England

C. The Queen of the England                                    D. the Queen of England

6. On Sunday mornings I stay in bed …………..8 o’clock.

A. until                                 B. at                             C. from                        D. to

7. I often ……………in winter.

A. go playing skiing                                       B. go skiing

C.play skiing                                                 D. go to ski

8. Some young peole are working ……………hospital volunteers.

A. to be                                B. such as                     C. like                          D. as

9. We shouldn’t cross the street outside the …………….

A. pavement             B. foot lane                   C. sidewalk                  D. zebra crossing

10. They …………..healthy after the summer vacation.

A. looked                  B. were seeming           C. were looking            D. were appearing

11. They meet their friends and …………some fun.

A. take                                 B. have             C. do                           D. enjoy

12. Yo should pay more …………….in class.

A. part                                 B. care                         C. notice                      D. attention

13. He and his friends usually get ……… and talk about their stamps.

A. together                B. themselves               C. each other                D. one another

14. He likes stamps. He is a stamp …………..

A. collect                              B. collecting                  C. collector                  D. collects

15. Some students say they are …………have no time for pastime.

A. hurry                                B. busy             C. full                           D. hard

16. It’s difficult to cross this street because there is too much ………..

A. crowd                              B. traffic                       C. people                     D. transport

17. There aren’t any good movies …………..at the moment.

A. going on                           B. being on                   C. performing               D. showing

18. Sorry I can’t come but thanks ………….

A. any ways                         B. any way                   C. anyway                    D. in anyway

19. Look at ………..girl over there.

A. one                                  B. this                           C. that                          D. a

20. Would you like to come to my house for lunch?

A. Yes, I do                         B. I’d love to                C. Yes, I like                D. OK. I’d like

1.My sister (go) goes to school at 7 o'clock every morning.

2.A:What are you (do ) doing Hoa?

   B:I'm helping my mum with the housework.

3.We can't go out now.It (rain) is raining very hard.

4.how do  you (go) go to school everyday?

5.My sister likes (cook) cooking very much.

6.Does your sister (listen) listen to music in her free time?

7.Someone (knock)is knocking at the door .Can you answer it?

8.Minh usually (do)does his homework in the evening .

9.Our school (be) is surrounded by mountains .

10.I (like) like maths but  I (not like) don't like English.