Xác định CTHH của các hợp chất sau:

a, A có khối lượng mol phân tử là 106g; thành phần % về khối lượng của các nguyên tố: 43,4% Na; 11,3% C còn lại là của O

b, B có thành phần phần trăm về khối lượng các nguyên tố: 38,61% k, 13,86% N còn lại là O

Cho tam giác cân ABC, AD là trung tuyến. Gọi M là trung điểm AC, E là điểm đối xứng với D qua M

a, tứ giác ADCE là hình gì

b, tứ giác AEDB là hình gì

c, Điều kiện gì của tam giác ABC để ADCE có 2 cạnh liên tiếp bằng nhau.( ko dùng hình vuông, hình thoi)

giúp mik nha

rewrite the following sentences based on the given words

1. All of the children of the Smith's really like playing rackets(keen)

2.The thing that I hate most is motor racing, and i will never do it in my life (detest)

3. The harvest festival in my hometown usally starts in October, but this year it started in the middle of september ( earlier)

4. It takes a buffalo about half of a day to plough that fiald, but a machine can do it with an hour ( faster)

5. In cities, classrooms are equipped with speakers, computer, projectors; however, classroom in the countryside don't have any( better equipped)

1.Jonny/ like/ play/ drum/ room/ whereas/ kenny/ enjoy/ gym/ fitness center/ weekends

2. Drive/ city/ be/ much/ stressful/drive/countyside

3.People/countryside/seem/have to / work/ hard/ people/city

4. clothing/ the muong women/ diversified/that/men

5. Muong/ be/fourth/largest/ ethnic minoruty group/ Vietnam/ Viet/ Tay/ Thai

A và B là 2 nguyên tố cơ bản có hóa trị không đổi, A tạo với O hợp chất AO, B tạo với H hợp chất BH. Xét công thức hóa học A và B

nguyên tử y có tổng số hạt là 46 số hạt không mang điện bằng số hạt ko mang điện. X/d nguyen tu x thuoc nguyen to nao

1. Ms. Jones isn't as nice Ms. Smith.

A. as B. for C. like D. to

2. The rooms in Graduate Towers are Patterson Hall.

A. larger than B. larger than that of C. larger than those in D. larger than in

3. Although she is very popular, she is not her sister.

A. pretty as B. as pretty C. prettier than D. most pretty than

4. Tuition at an American university runs …… six thousand dollars a semester.

A. so high as B. as high to C. as high as D. as high than

5. Everyone looks much today than they did yesterday.

A. happy B. happily C. more happily D. happier

6. Mr. Brown receives a salary than anyone else in the company.

A. big B. more bigger C. bigger D. the bigger

7. The Boeing 747 is twice the Boeing 707.

A. bigger than B. as bigger as C. as big as D. more bigger than

8. "Do you know that beautiful lady over there?" "Yes, that's Wanida. She's in her group.

A. more beautiful than any girl B. more beautiful than any other girl C. so beautiful as other girl D. beautiful more than another girl

9. My young brother grew very quickly and soon he was my mother.

A. more big than B. so big than C. as big as D. too big than

10. He is not ……………………tall as his father.

A. the B. as C. than D. more

11. John’s grades are ……………… than his sister’s.

A. higher B. more high C. more higher D. the highest

12. Deana is the …………………… of the three sisters.

A. most short B. shorter C. shortest D. more short

13. She speaks English as ………………. as her friend does.

A. good B. well C. better D. the best

14. Of the three shirts, this one is the ………………… .

A. prettier B. most prettiest C. prettiest D. most pretty

15. The baby’s illness is ………………… than we thought at first.

A. bad B. worst C. worse D. badly

16. Today is the ………………… day of the month.

A. hot B. hotter C. hottest than D. hottest

17. He works more ………………… than I.

A. slow B. slowly C. most slowly D. slowest

18. My book is as …………………. as yours.

A. good B. well C. better D. the best

2 0. It’s … … to go by bus than by car.

A. cheaper B. cheapest C. more cheap D. more cheaper

2 1. That house is… … … one on the street.

A. oldest B. the oldest C. old D. older

22. This hotel must be ……………… than the small one next door.

A. expensive B. more expensive C. the most expensive D. the more expensive

23. An orange is ……………… than a plum

A. more large B. more larger C. larger D. the largest

4. What is the ……………… thing you have ever done?

A. more difficult B. most difficult C. difficulty D. difficult than

25. This river is than that river.

A. narrow B. narrowest C. narrower D. most narrow

26. The test is not ………….… difficult ……………… it was last month.

A. as / as B. so / as C. more / as D. A and B

27. Peter usually drives ………………… Mary.

A. more fast B. more fast than C. faster than D. B and C

28. My brother sang of all the pupils of the group.

A. more beautifully B. the most beautifully C. less beautifully D. most beautifully 29. At 3,810 meters above sea level in Bolivia stands Lake Titicaca, … … in t h e wo rld.

A. the highest large lake B. largest high lake C. high largest lake D. the high largest lake

30. The hotel was ...... any one we had stayed at before.

A. more expensive than B. more expensive as C. most expensive than D. better expensive than

31. A: It's a long way from Britain, isn't it?

B: Yes, but it isn't as........ as Hong Kong.

A. far B. farther C. farthest D. further

Nếu  a ⋮ 3  và  b ⋮ 3 thì

A. (a+b):3

B. (a-b) ⋰ 3

C. (a+b):6

D. (a+b) ⋮ 9