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a,A= 1+2+2^2+2^3+ ...+ 2^100 b, B= 3^200+3^198+3^196+...+ 3^2+ 1 c, C =1/4+ 1/4^2 + 1/4^3 + ... + 1/4^2021 d, D= 1/5 + (1/5) ^ 3 + ( 1/5) ^5 +...+ (1/5) ^2021 e, E= 3^100- 3^99+ 3^98 - 3^97 + ...+ 3^2 - 3 + 3^0
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Ex 11. Write questions for the underlined parts. 1. A: _______________________________________________________________ B: My hobby is photography. 2. A: _______________________________________________________________ B: I started my hobby five years ago. 3. A: _______________________________________________________________ B: I enjoy my hobby because I think it’s creative. 4. A: _______________________________________________________________ B: I spend two hours a day on my hobby. 5. A: _______________________________________________________________ B: Jim usually plays volleyball in his free time. 6. A: _______________________________________________________________ B: He plays volleyball three times a week. 7. A: _______________________________________________________________ B: He often plays volleyball at the court near his school. 8. A: _______________________________________________________________ B: He likes to play volleyball with his friends. Ex 12. Fill in each blank with a word from the box. kinds classify books near name collection clean immediately Collecting (1) __________ is my favourite hobby. I started my hobby five years ago. The first item in my (2) __________ is a book about Doraemon. And now I have a lot of books of all (3) __________: comics, children's, history, science, detective, adventure, etc. Whenever I find an interesting book I buy it (4) __________ . I usually buy books in the bookstores (5) __________ my school and my house. Sometimes my relatives and my friends give me books as a gift. I (6) __________ my books into different categories and put each category in one corner of my bookshelf with a (7) __________ tag on it. It takes all my free time to keep everything (8) __________ and dusted. It keeps me amused for hours, too.

Ex 9. Choose the correct verb form or tense. 1. I’m told you are ill. I hope you __________ better again. a. will feel b. feel c. are feeling d. don’t feel 2. We were getting tired, so we stopped __________ lunch. a. have b. having c. to have d. for having 3. __________ you __________ to school every morning? a. Does ... walk b. Do ... walk c. Will... walk d. Are ... walking 4. He enjoys __________ cycling at the weekend. a. to go b. going c. goes d. go 5. You needn’t wear your coat. It __________ cold today. a. will be b. won’t be c. doesn’t be d. is 6. We __________ swimming because it’s fun and good exercise. a. like b. are liking c. will like d. liked 7. My grandparents don’t like __________ in the city because It’s noisy and crowded. a. live b. lived c. living d. to living 8. Fire needs oxygen to burn. It __________ without oxygen. a. burn b. burns c. don’t burn d. doesn’t burn 9. How much time do you spend __________ the internet per day? a. surf b. to surf c. surfing d. to be surfing 10. I don’t mind __________ a DVD, but I prefer __________ to the cinema. a. to watch - to go b. watching - go c. to watch - going d. watching - to go Ex 10. Fill in each blank with a suitable preposition. 1. Hi, everyone. Welcome __________ my house! 2. Is there anything good __________ television tonight? 3. What do you like doing __________ your free time? 4. He takes photographs __________ a hobby. 5. Will you take __________ making pottery in the future? 6. He is interested __________ collecting toy cars. It’s his favourite hobby. 7. __________ weekends, we usually go fishing in the river. 8. My cousin always gives me gifts __________ special occasions.

Exercise 3: Hoàn thành đoạn văn sau bằng cách chia động từ để điền vào chỗ trống Tomorrow, students _____ (assemble) in the school playground at 08:00 am, to go to Heritage Village. They ___ (have) their school picnic. The bus _____ (arrive) at 08:30 am, sharp. We ____ (reach) the Heritage Village at around 10:30 am. On reaching, students _____ (go) around to see various displays. The staff at the spot _____ (welcome) the students with flowers and sented perfumes. They _____ (offer) the students snacks. After they eat their snacks, children _____ (play) in the park. Around 01:00 pm, all students ____ (assemble) for lunch. They ____ (sit) in a circle and _____ (sing) songs. At around 04:00 pm, students ____ (gather) near the bus. They ____ (board) the bus in a queue. At around 06:00 pm, they ____ (reach) school. Their parents ____ (pick) them up from the school.

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