Bạn Thùy có 100 cái vòng giun trong một cái hộp. Trong đó có 35 cái màu xanh, 23 cái màu vàng và 42 cái màu đỏ. Hỏi nếu không nhìn vào hộp thì bạn phải lấy ít nhất bao nhiêu cái vòng trong hộp ra để có chắc chắn 25 cái cùng màu ?

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Ex 1: Read and answer the questions. The Robinsons had a great holiday in Nha Trang. Unfortunately, the holiday soon ended and it was time to return home. They took a bus back to Hanoi. Liz was excited as the bus drove through the countryside. She saw rice paddies for the first time. Everything looked calm and peaceful. At four o’clock, the bus stopped at a small roadside restaurant for ten minutes. Mr. Robinson was asleep, so Mrs. Robinson bought some peanuts and an ice cream for Liz. The bus arrived in Hanoi at about 7 pm. 1. Where did the Robinsons go on holiday? 2. How did they come back to Hanoi? 3. What did Liz see? 4. What time did Mrs. Robinson buy? 5. What time did they arrive in Hanoi? Ex 2: Circle the word or phrase (A, B, C or D) that best completes each sentence. 1. We ___________ our grandparents next week. A. visit B. will visit C. visited D. to visit 2. How ___________ is the blue hat? It's 50,000 dong. A. far B. many C. old D. much 3. What about ___________to school every morning? A. going B. go C. to go D. went 4. The nurse __________ Lan's temperature yesterday. A. will take B. took C. is taking D. takes 5. I usually ___________football. A. will play B. is playing C. play D. played 6. Where..... they..... their summer vacation next year? A. do/ spend B. will/ spend C. did/ spend D. are/ spend 7. Look! The students..... badminton in the school yard. A. play B. played C. are playing D. A&B 8. My sister..... a new book yesterday morning. A. will buy B. is buying C. buys D. bought