Tính nhanh N=\(\frac{1}{1.5}+\frac{1}{5.10}+\frac{1}{10.15}+\frac{1}{15.20}+...+\frac{1}{2005.2010}\)
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\(\frac{S_{APN}}{S_{PNC}}=\frac{AN}{NC}=\frac{1}{3}\)(chung đường cao kẻ từ P)
\(S_{PNC}=100x3=300cm^2\)
\(\frac{S_{BNM}}{S_{NMC}}=\frac{BM}{MC}\)( chung đường cao kẻ từ N). mà 2 tam giác chung đáy NM nên đường cao hạ từ B bằng đường cao hạ từ C
Vậy \(S_{PBN}=S_{PNC}=300cm^2\)(chung đáy PN, đường cao kẻ từ B băng đường cao kẻ từ C)
\(S_{ABN}=S_{PBN}-S_{PAN}=300-100=200cm^2\)\(\frac{S_{ABN}}{S_{ABC}}=\frac{AN}{AC}=\frac{1}{4}\)(chung đường cao kẻ từ B)
\(S_{ABC}=200x4=800cm^2\)
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D-WRITING:
Question VI. Make sentences, using the words and phrases provided (1.5point)
1. Tippping/ not/ custom/ Viet Nam/ so/ you/ not/ have/ tip/ if/ don’t want.
…………………Tipping is not a custom in Viet Nam, so you don't have to tip if you don't want to.………………………………………
2. In Brazil/ standard/ tip/ in/ restaurant/ be 10 percent.
………………………………In Brazil, the standard tip in restaurants is 10 per cent.……………………………….
3. The xoe dance/ performed/ the boys and girls/ the hamlets.
……………………The xoe dance was performed by the boys and the girls in the hamlets.……………………………………………
4. We/ have/take/ shoes/ when/ we/ inside/pagoda.
……………………We have to take oà your shoes when we go inside a pagoda.……………………………………….
5.Nowadays/ teenagers/ rely/ technology/ than/ the/ past.
…………………………Nowadays teenagers rely on technology more than in the past.……………………………..
6.Life/ the countryside/ changed/ a lot/ the/ ten /years.
………………………Life in the countryside has changed a lot over the past ten years.………………………………
ĐỀ SỐ 2
Question I. Find the word which has different sound in the part underlined. ( 1 point)
1. A. mention B. question C. action D. education
2. A. listened B. opened C. wanted D. lived
3. A. community B. computer C. museum D. customs
4. A. needed B. opened C. wanted D. decided
Question II. Choose the best answer A, B, C , or D to complete the sentences. (2. 5 points)
1. You should ____________ information about a custom or tradition.
A. finds B. found C. finding D. find
2. A tradition is something we do that is special and ____________ down through the generations.
A. to passed | B. passed | C. passing | D. is passing |
3. In the UK, there are lots of customs for table manners. For example, We ____________ use
a knife and fork at dinner.
A. have to B. are having C. has to D. having to
4. In Viet Nam, you____________ use only the first name to address people older than you.
A. should B. must C. shouldn’t D. have to
5. At the Mid-Autumn Festival ,kids can sing, dance, and enjoy moon-cakes ; ____________, every child s it very much.
A. However B. Moreover C. Because D. Therefore
6. In 2010, Ha Noi____________ its 1000th anniversary.
A. celebrated B. commemorated C. worshipped D. remembered
7. Tet is an occasion for family____________ in Viet Nam.
A. visitings B. Meeting C. reunions D. seeings
8. ____________ spring comes, many Vietnamese villages prepare for a new festival season.
A. While B. When C. Nevertheless D. However
9. People burn incense to show respect to their ____________ during Tet.
A. relatives B. ancestors C. friends D. neighbors
10. The Le Mat Festival ____________ the founding of the village.
A. worships B. commemorates C. performs D. preserves
Question III. Give the correct form of the following verbs: ( 2.0 points)
1. Peter ____________played ________ football yesterday. (play)
2. When I came, the whole family _________was having _____ dinner around a big dining table. (have) |
3. Children should______take_______ things from adults with both hands. (take) 4. My father and I ___get_______ up at 5 o’clock every morning. (get) 5. They ______are learning___________ English at the moment. ( learn) 6.We ______________went______ to Hung King Festival since last Sunday. (go) 7. Before leaving the dinner table, _____does____your son _____have to___ ask for permission? (have to) 8.When I _____came______ ,the whole family was having dinner around a big dining table. (come) |
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Ex1: Choose the best answer:
Question 1: Do you know what is the cause __________ pollution?
A. of B. in C. on D. for
Question 2: My mother has to measure blood __________ every month
A. billboard B. pressure C. groundwater D. earplug
Question 3: __________ pollution is harmful or annoying level of noise, as from vehicles, industry activities, etc.
A. light B. visual C. soil D. noise
Question 4: Parents should teach children not to __________ wastes on the road
A. litter B. poison C. cause D. measure
Question 5: I can’t hear your voice __________ I’m wearing an earplug
A. although B. due C. however D. because
Question 6: His grandfather made him __________ hard when he was small
A. study B. to study C. studying D. studied
Question 7: This picture __________ the contamination of ground water.
A. illustrate B. illustrating C. illustrates D. illustrated
Question 8: Could you list some non-point source __________?
A. pollution B. pollutants C. polluting D. polluted
Question 9: Scientists has just come up __________ a solution to hearing loss
A. to B. on C. with D. down
Question 10: If we dump a plas into the ground, it __________ a long time to disappear.
A. will take B. take C. took D. takes
Question 11: Pollutions are harmful __________ human health
A. with B. at C. to D. on
Question 12: __________ water resulted in the death of many aqua animals.
A. Contaminate B. Contaminated C. Contaminating D. Contamination
Question 13: What would you do if a factory in your neighborhood __________ untreated water into the river?
A. dump B. dumped C. dumping D. dumps
Question 14: Have you ever heard about the __________ of radioactive pollution?
A. affects B. effects C. pollutes D. poisons
Question 15: : __________ pollution is the increase of temperature caused by human activity.
A. visual B. water C. thermal D. radioactive
Ex2: Supply the correct form of the verbs in brackets
1. Lan often (do) ____does______ her homework.
2. They (play) ______are playing____ tennis now.
3. Lan (buy) ___has bought______ a car since 2000.
4. Minh (watch) ___watched____ TV last night.
5. Hoa (meet) ____will meet_____ Lan tomorrow.
6. Football (play) _____is played___ by boys.
Chào em, em tham khảo nhé!
Ex3: Find and correct mistakes:
1.What about watch TV?
A. What B. about C. watch => watching
2.Do you mind if I listened to music?
A. mind B. listened => listen C. to
3.What do you do yesterday?
A. What B. do => did C. yesterday
4.My dog is different with her dog.
A. is B. with => from C. her
Ex4: Rewrite sentences without changing the meaning.
1. Let’s go to the zoo!
What about going to the zoo?
2. Ba enjoys skipping.
Ba s skipping/to skip.
3. Long should work harder.
Long ought to work harder.
4. Would you mind opening the door?
Do you mind opening the door?
4. I can’t tell you unless you tell me what’s wrong. (if)
-> If you don't tell me what's wrong, I can't tell you.
5. Nhung didn’t go to the cinema with her friends because her younger sister was ill.
-> Because of her illness, Nhung didn't go to the cinema with her friends.
6. Eating too much sugar can result in health problem. (lead to)
-> Eating too much sugar can lead to health problem.
7. Minh isn’t hard-working, so he often gets bad marks. (if)
-> If Minh were hard-working, he wouldn't get bad marks.
8. I’m not you. But I think you should recycle these plas carrier bags. (If)
-> If I were you, I would recycle these plas carrier bags.
Ex5: Use the correct form of the words given to complete the sentences.
1. This volcano is dead; it has been (ACT) inactive for more than a century.
2. The Earth would be a happy planet if human beings, animals and plants (PEACE) peacefully co-existed.
3. The chemical (POLLUTE) pollutant from cars and factories make the air, water and soil dangerously dirty.
4. You cannot imagine how (SERIOUS) serious the area was damaged by the flood.
5. Scotland is a legendary land and this is noted for its rich and interesting history. (legend)
Chúc em học tốt và có những trải nghiệm tuyệt vời tại olm.vn!
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Do (SAB) và (SAC) vuông góc với đáy (ABC)
Và (ABC) ∩ (SAC) = SA nên SA ⊥ (ABC)
BC ⊥ AH, BC ⊥ SA
⇒ BC ⊥ ((SAH)
Mà BC ⊂ (SBC) nên (SAH) ⊥ (SBC)
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Bài 2.Từ văn bản "Bài học đường đời đầu tiên", em rút ra được bài học cho mình là:
- Bài học về tính kiêu căng, hỡm hĩnh, xốc nổi của Dế Mèn.
- Bài học về lòng bao dung độ lượng, biết cảm thông và tha thứ của Dế Choắt.
- Bài học về cách biết kiềm chế, không nên nóng nảy, tự ái của chị Cốc.
- Bài học về lòng nhân ái, biết yêu thương giúp đỡ những người yếu hơn mình.
Bài 3a.
- Những câu văn có sử dụng phép so sánh trong bài thơ Vượt thác là:
“Thuyền rẽ sông lướt bon bon như đang nhớ núi rừng phải lướt cho nhanh để về cho kip.”
“ Những động tác thả sào, rút sào rập ràng nhanh như cắt.”
“Dượng Hương Thư như một pho tượng đồng đúc, các bắp thị cuồn cuộn, hai hàm răng cắn chặt, quai hàm bạnh ra, cặp mắt nảy lửa ghì trên ngọn sào giống như một hiệp sĩ của Trường Sơn oai linh hùng vĩ."
"Dọc sườn núi, những cây to mọc giữa những bụi lúp xúp nom xa như những cụ già vung tay hô đám con cháu tiến về phía trước."
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SA vg (ABC)=> SAB,SAC vuông
SA vg BC, AB vg BC => BCvg (SAB) =>SB vg BC=> SBC vuông
vậy all mặt đều vuông
\(\hept{\begin{cases}SA\perp\left(ABC\right)\\AB\subset\left(ABC\right)\end{cases}}\) \(\Rightarrow SA\perp AB\Rightarrow\) tam giác SAB vuông (1)
\(\hept{\begin{cases}SA\perp\left(ABC\right)\\AC\subset\left(ABC\right)\end{cases}\Rightarrow AC\perp SA\Rightarrow}\) tam giác SAC vuông (2)
Tam giác ABC vuông tại B (gt) (3)
\(\Rightarrow AB\perp BC\)
\(\hept{\begin{cases}SA\perp\left(ABC\right)\\BC\subset\left(ABC\right)\end{cases}\Rightarrow SA\perp BC}\)
\(\hept{\begin{cases}AB\perp BC\\SA\perp BC\end{cases}\Rightarrow\hept{\begin{cases}BC\perp\left(SAB\right)\\SB\subset\left(SAB\right)\end{cases}\Rightarrow}SB\perp BC\Rightarrow}\) Tam giác SBC vuông (4)
\(\left(1\right);\left(2\right);\left(3\right);\left(4\right)\Rightarrowđpcm\)
= 1 - \(\frac{1}{2010}\)nha em
#Chúc em học tốt
\(N=\frac{1}{1.5}+\frac{1}{5.10}+\frac{1}{10.15}+...+\frac{1}{2005.2010}\)
\(5N=\frac{5}{1.5}+\left(\frac{5}{5.10}+\frac{5}{10.15}+...+\frac{5}{2005.2010}\right)\)
\(5N=1+\left(\frac{1}{5}-\frac{1}{10}+\frac{1}{10}-\frac{1}{15}+...+\frac{1}{2005}-\frac{1}{2010}\right)\)
\(5N=1+\left(\frac{1}{5}-\frac{1}{2010}\right)\)
\(5N=1+\frac{401}{2010}\)
\(5N=\frac{2411}{2010}\)
\(\Rightarrow N=\frac{2411}{10050}\)