một tấm bìa HCN có chu gấp 5 lần CR. Nếu tăng CR thêm 9cm, tăng CD thêm 4cm thì miếng bìa thành một hình vuông .Tính DT ban đầu của miếng bìa

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IV. Fill in the blanks with a correct form, the PAST SIMPLE or the PAST CONTINUOUS: 1. I ____ (call) Mr Wilson at 9 last night, but he (not be)_________at home. He (study) ____ at the library 2. I _________ (not hear) the thunder during the storm last night because I ___________ (sleep) 3. It was beautiful yesterday when we went for a walk in the park. The sun___(shine). The birds_____(sing) 4. My brother and sister _______ (talk) about something when I ____________ (walk) into the room. 5. Tom went to his friends ‘house, but the boys __________ (not be) there. They (play)_____soccer in thevacant lot down the street. 6. The little boy _______ (fall) asleep while his mother____________ (read) him a story. 7. I really enjoyed my holiday last January. While it______(snow) in Iowa, the sun _____ (shine) in Florida. 8. While Ted _____ (shovel) snow from his driveway yesterday, his wife ____________ (bring) him a cup of hot chocolate. 9. John ___ (have) a car accident last week. He _________ (drive) down the street when suddenly a lorry _____________ (hit) his car from behind. 10. Ten years ago, the government ____________ (decide) to begin a food programme. At that time, many people in the rural areas _______________ (starve) due to several years of drought. 11. They ___________________(wait) for me when I _________________ at the station (arrive) 12. She ________________ (swim) in the sea when I ___________________ her (see) 13. _______________they_________________(play) tennis when it _________________ raining (start)? 14. We _________________ (drive) home from the theatre when the police __________________(stop) us. 15. The wind __________________ (blow) very hard when I ________________(go) out this morning. Giúp mình với ạ... :((