calli: Study hard on you will pass the exam. Có tâm, có trang trí, :>

cho tam giác ABC vuông tại A, đường cao AH. AB=3cm; AC=4cm. Kẻ HD ⊥ AB; HE ⊥ AC. Chứng minh BD=BC. cos ³B

Cho hình chữ nhật `ABCD`, kẻ `CH` vuông góc `BD`, `AH` cắt `BC` tại `E`, `DE` cắt `CH` tại `I`, `BI` cắt `CD` tại `F`. CMR: `HD` là tia phân giác `\hat{AHF}`

1. We help him every year. =>He…………………………………… 2. She plays badminton in Hoang Hoa very often. => Badminton…………………………… 3. They usually carve wood in the evening. => Wood…………………………………… 4. Mr. Mathew surfs the Webs on Sunday. => The Webs ………………………… 5. These boys ride horses every Sunday.(ridden) => Horses………………………………… 6. They do gymnastics every weekend to keep fit and stay healthy.(done) => Gymnastics…………………………… 7.Mary has collects bottles every two weeks => Bottles………………………………… 8. Bat Trang usually makes pottery.(made) => Pottery is usually…………………… 9. My parents make models for us in the evening. => Models are………………………… 10.David eats a lot of junk food.(eaten) => A lot…………………………………

Mọi ng ơi giúp mình gấp lắm ạ:<<<< vote 5 sao ạ...........................................................................................

giúp e câu b và c thui nhé e cám ơn nhìu nha!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Exercise 2 1. I _______my homework as soon as Lan goes here. a. will finish b. will be finishing c. finish d. will have finished 2. Ask her to come ad see me when she ________ her work. a. finish b. has finished c. finished d. finishing 3. After you finish your work, you________ a break. a. should take b. have taken c. might have taken d. takes 4. Oil________ if you pour it on water a. floated b. floats c. will be floated d. float 5. When he returned home, he found the door________. a. unlocking b. unlocked c. to be unlocked d. have unlocked 6. That dancing club________ north of the city a. lays b. lies c. locates d. lain 7. Almost everyone________ for home by the time we arrived. a. leave b. left c. leaves d. had left 8. By the age of 25, he ________ two famous novels. a. wrote b. writes c. has written d. had written 9. While her husband was in the army, Janet________ to him twice a week. a. was writing b. wrote c. was written d. had written 10. I couldn't cut the grass because the machine_______ a few days previously. a. broken down b. has been broken c. had broken down d. breaks down 11. We ________English this time last week. a. learned b. were learning c. have learned d. had learned 12. Is it raining? - No, it isn't but the ground is wet. It________ a. rained b. had rained c. has rained d. has been raining 13. Her family________ to America before 1975. a. went b. have gone c. had gone d. would go 14. When I arrived at the party, Martha________ home already. a. went b. have gone c. had gone d. would go 15. Henry________ for 10 years when he finally gave it up. a. has smoked b. has been smoking c. had smoked d. had been smoking' 16. Yesterday morning I got up and looked out of the window. The sun was shinning but the ground was very wet. It________ a. rained b. has been raining c. had rained d. had been raining 17. We ________ our examination next month. a. have b. shall have c. will have had d. will be having 18. Look that those black clouds! It________ a. is going to rain b. will rain c. would rain d. can rain 19. We________ English this time next Monday. a. learn b. will learn c. are learning d. will be learning 20. We________ this course before the final examination. a. are going to finish b. have finished c. will finish d. will have finished

1, a, 32 ≤ 2 $2^{x}$ ≤ 2 $2^{2x-3}$ . $2^{8-2x}$ b, $4^{15}$.$9^{15}$ < $2^{x}$. $3^{x}$ < $18^{16}$.$2^{16}$ giúp mình với!

Mọi người cho em hỏi khi nào mới chọn chiều dương là chuyển động của xe, chiều âm là chuyển động của xe ạ em xin cảm ơn

Cho n đường thẳng cắt nhau tại O, Hỏi có bao nhiêu cặp góc đối đỉnh không kể góc bẹt