Mark the letter A, B, C or D to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
 31. Coal is limited and it can be replaced by renewable sources.
A. finite B. abundant C. effective D. alternative 32. Solar energy is plentiful and it can be replaced easily.
A. a few B. limited C. abundant D. harmful
33. Coal, oil, natural gas are all non-renewable energy sources, so they can be used up.
A. ran out of B. ran over C. ran up D. ran to 

27. It’s pretty late, Lan ______ a project ___ energy sources. A. is doing/ on B. does/ about C. will do/ on D. do/ about

21. The workers are putting __________ on the roof of my house
A. light bulb B. wind turbine C. solar panel D. heater
22. For many people living in rural areas, biogas is a(n) ________ source of energy.
A. expensive B. harmful C. polluting D. cheap
23. Nuclear energy can provide enough electricity for the world's needs, but it is __________.
A. cheap B. clean C. dangerous D. renewable
24. Hydro energy is expensive because it requires __________.
A. dams B. solar panels C. animals D. chemicals
25. I _______ in the room right now.
A. am being B. was being C. have been being D. am

51. Tidal energy is renewable, ___________________and clean. (plenty)
52. Solar energy is_____________________, plentiful and clean. (renew)
53. I think that solar energy can be an_____________________ source of energy in the near future. (alter)
54. We should reduce the use of________________ at home. (electrical)
55. Scientists are looking for clean and ____________ sources of energy. (effect) 

46. Many countries/ using/ solar energy.
A. Many countries are using the solar energy.
B. Many countries are using solar energy.
C. Many countries is using solar energy.
D. Many countries using the solar energy.
47. save/energy/one/best/way/conserve/natural/resources.
A. Saving energy is one of the best way to conserve natural resource.
B. To save energy are one of the best ways conserving natural resource.
C. To save energy are one of best ways to conserve natural resource.
D. Saving energy is one of the best ways to conserve natural resource.
48. most/ our electricity/ come/ use/ coal, gas, or oil.
A. Most our electricity come from using of coal, gas, or oil.
B. Most our electricity comes from using of coal, gas, or oil.
C. Most of our electricity are coming from the use of coal, gas, or oil.
D. Most of our electricity comes from the use of coal, gas, or oil

chứng tỏ các đa thức sau không có nghiệm
c) \(\left(x+2\right)^2+1\)
d) \(x^4+2019\)

viết một đa thức một biến có 3 hạng tử mà  hệ số cao nhất là -3 và hệ số tự do là 2

1.       Cho tam giác MNP cân tại M,Q là trung điểm của NP.A, B thuộc NP sao cho NA = PB.Kẻ AH vuông góc MN tại H, BK vuông góc với MP tại K và AH cắt BK tại O
a) tam giác MNQ = tam giác MPQ
b) tam giác MNA = tam giác MPB
c) MH=DK : M,Q,O thẳng hàng

Dựa vào kiến thức đã học, hãy nêu hiểu biết của em về nam châm vĩnh cửu