Thông thường, tai người có thể nghe đc âm có tần số bao nhiêu? Những tần số dưới 20 Hz là gì? Những âm có tần số lớn hơn 20000Hz gọi là gì ? Những động vật nào có thể nghe đc tần số thấp?

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VII. Read the passage and then decide whether the sentences are True or False Vietnam’s New Year is known as Tet. It begins between 21st January and 19th February. The exact date changes from year to year. Tet lasts ten days. The first three days are the most important. Vietnamese people believe that what people do during those days with influence the whole year. As a result, they make every effort to avoid arguments and smile as much as possible. Vietnamese people believe that the first person through the door on New Year’s Day can bring either good or bad luck. Children receive lucky money as they do in other countries 31. Tet occurs in late January and early February …………………. 32. There are two weeks for Lunar New Year ………………… 33. People should not argue with each other at Tet ………………… 34. The first visitor on New Year’s Day brings good or bad luck ………………… 35. Only children in Viet Nam get lucky money ………………… VIII. Choose the correct answer to fill in the blank Television first came about 60 years ago in the 1950s. Nowadays, it is one of the most (36)………….. sources of entertainment for both the old and the young. Television brings (37)……………….for children, world news, music and many other (38)………………If someone likes sports, he can just choose the right sports (39)……………It is not difficult for us to see why (40)……………is a TV set in almost every home today. 36. A. cheap B. expensive C. popular D. exciting 37. A. news B. cartoons C. sports D. plays 38. A. sets B. reports C. channels D. programmes 39. A. athletes B. channel C. time D. studio 40. A. it B. this C. that D. there