giúp mình với, tks~ Cho tam giác ABC có AB = AC. Gọi BD,CE là 2 đường cao hạ từ B và C xuống AC và AB,BD và CE cắt nhau tại I. Chứng minh : a) BD = CE b) ID = IE

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EX 1: (httd + qkd) 1. Look! He__________from a large whisky-bottle. A. drinks B. is drinking C. will drink D. drank 2. Mike_____one hour ago. A. phoned B. was phoning C. had phoned D. has phoned 3. We ________English this time last week. A. learned B. were learning C. have learned D. had learned 4. Her family________ to America before 1975. A. went B. have gone C. had gone D. would go 5. In the last two decades, space exploration ___great contributions to weather forecasting. A. is making B. has made C. made D. makes 6. Tim saw his friends while he ________ Hai Ba Trung street. A. was crossing B. cross C. is crossing D. crossed QKHT Before = By the time/ when QKĐ, S + QKHT Eg: I had live in Hue before 1975 When I got up this morning, my father had already left. 7. The city has changed a lot since I last ( visit) it. 8. Her academic performance has greatly improved since she (change) study methods. 9. Mary has been financially independent since she ( go )out to work. 10. The air quality in this area has improved a lot since that factory (close) 11. The teacher (enter) the room while the students were discussing their plan for the excursion. 12. Linda (take) great photos of butterflies while she was hiking in the forest 13. The children were flying their kites in the field when it (start) to rain BỊ ĐỘNG HIỆN TẠI ĐƠN 1.The flowers ____________ by her in the morning. A.water B. are watered C. were watered D. watered 2. The eggs ______by Susan every afternoon. A. collect B. are collected C. were collected D. collected 3. Old furniture _____at the end of the street every weekend. A. is sold B. sell C. has been sold D. will be sold 4. Cup cakes ________ for the cat by Nick every day. A. are made B. made C. have been made D. make 5. A story______by my mother before sleeping every night. A. is told B. tells C. told D. was told 6. English _______almost everywhere. A. is spoken B. has been spoken C. speaks D. will speak 7. Linda ______to school everyday. A. is taken B. takes C. was taken D. has been taken 8. Many children ______ by violent games everyday. A. are influenced B. were influenced C. influence D. influenced CÂU GIÁN TIẾP 1. She asked me ________. A. if I was good at English C. if I good at English B. if was I good at English D. if I am good at English 2. She asked me where I _______ from. A. come B. came C. to come D. coming 3. My father asked me__________ about the film A. what I think B. what do C. what I thought D. what did I think 4. The students said that they ______their work the following week. A. would finish B. finished C. will finish D. finish 5. She said to me that she __________ to me the Sunday before. A. wrote B. has written C. was writing D. had writing 6. They told their parents that they___________ their best to do the test. A. try B. will try C. are trying D. would try 7. John asked me _______ that film the night before. A. that I saw B. had I seen C. if I had seen D. if had I seen 8. The guest told the host that _______. A. I must go now B. he must go now C. he had to go now D. he had to go then