cho tam giác abc vuông tại a đường cao ah = 15cm,ab/ac=5/7.tính độ dài hc,hc ( giải giúp e với ạ )

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Giúp e ạ Exercise 3: Complete the following sentences, using the forms of the verbs in past continuous ​1. (What/ you/ do) …………………………. at this time yesterday? 2. (He/ not/ look) ………………….. at me when I waved to him. 3. (You/ have) ………………….. a date when I saw you last night? 4. (Where/ they/ go) ………………… while I was calling you this morning? 5. (Why/ you/ not/ wear) …………………. your old clothes when repairing the car? 6. (It/ not/ rain) …………………….. when we went out so we left the umbrella at home. 7. (Maria/ not/ drive)………………………..fast when the accident happened. So what was the reason? 8. (What/ your friend/ do)………………………. while you were going out eating with me last night? 9. During the 1990s, (we/ not/ cooperate) ……………. with any local firms but with foreign companies. 10. (They/ not/ study) ……………….. the whole morning yesterday because they told me they were tidying their rooms at that time. Exercise 4: Use the given words or phrases to complete the sentences ​when, while, at that time, all the morning yesterday, at 5p.m last week ​1. …………………….. I was playing football, I broke my arm. 2. Jim and Anna were crossing a wood ……………..it rained. 3. We built this house in 2000. ………………….., we were working in the same company. 4. ………………. the teacher was trying to explaining something, some students weren’t listening to her. 5. The victim was sleeping …………….. Luckily, in the afternoon she woke up. 6. The little boy was helping his dad fix the car ……………..the girl was helping her mum cook. 7. The child was crying …………………because his mother wasn’t at home from 8a.m to 11a.m. 8. My parents were having a birthday party in a restaurant ………………. so that evening I stayed at home and had dinner alone. 9. ……………….. she came back home, her children were sleeping well. 10. He graduated in 2009. ……………….., the economy was facing a global crisis so he couldn’t find a job.