Trong tay chỉ có một nam châm thử, liệu ta có thể nhận biết được một trong dây dẫn có dòng điện chạy qua hay không. Hãy trình bày cách nhận biết đó.

Các câu hỏi liên quan

VI)-Read the passage, and write the correct form of each verb in brackets. Use the past perfect, or the simple past (active or passive). Typhoon Linda in Viet Nam During the night of November 2, 1997, Typhoon Linda (44. hit) __________South Viet Nam, and (45. affect)___________ all the Southwestern provinces. Before the disaster (46. occur)____________, the Government of Viet Nam (47. warn) _________ populations in the areas. Moreover, the government (48. instruct) ___________ the provinces to combat the effects of the typhoon. Thanks to these efforts, more than 3,500 fishermen (49. rescue)____________. However, 464 people (50. kill) _________, over 3,000 boats (51. sink)_____________, and about 100,000 houses (52. destroy) _____________. The Government also (53. take) ___________ all measures to provide health and other services to the affected population. VII)-Fill in each blank with ONE suitable word. Drought Drought occurs when there is a (54)______________ of rainfall over a long period of time, resulting in water shortages for groups of people, activities or the (55) _____________. Droughts have a significant effect (56)___________ agriculture and can harm the economy. Water vapour needs to rise high through the atmosphere in order to form (57) _____________. However, in (58)____________ of high pressure, water vapour does not rise and no rain or clouds will form. When the high pressure stays in an area for a prolonged length of (59)____________, the result is drought,. cứu tớ!!!

II. Find the word which has a different STRESS in the part underlined. 4. A. factor B. bilingual C. imitate D. openness 5. A. translate B. mistake C. dictionary D. official 6. A. flexibility B. multinational C. inaccessible D. expensive III. Choose the correct answer to complete the sentences. 7. If only I ................... more careful, I might be better at getting good marks. A. am B. were C. be D. been 8. When I worked in Canada, I could communicate with people there in French but now I’m a ..................... rusty. A. many B. much C. little D. some 9. English today is the most ..................... spoken language in the world. A. widely B. early C. quickly D. largely 10. When we don’t know what an English word means, we often look it ...................... in an English-Vietnamese dictionary. A. on B. in C. at D. up 11. Mai can speak Chinese much more ................. than her brother can. A. fluent B. fluently C. fluency D. more fluently 12. The picture reminds him of the time ...................... he studied in Bangkok. A. which B. where C. when D. while 13. They could understand our conversation if they .................. some English. A. knew B. would know C. will know D. know 14. Ly has worked for a bank in London for 3 years and she speaks English ................... A. by well very now B. very well by now C. very by well now D. by very well now 15. In some countries, besides their ................... tongue, students have to learn another language. A. official B. second C. mother D. first 16. If Tuan .................... to England, it will be a good opportunity for him to improve his English. A. comes B. came C. has come D. will come IV. Find the underlined part that needs correction. 17. She can’t speak a word with Japanese because she finds it really hard to understand. A B C D 18. My friend - Jane has learnt Vietnamese for 3 years, so she is fluent at Vietnamese. A B C D 19. Her family has a cat who has three kittens. A B C D 20. It is said that many English words have been simple over the centuries. A B C D