Cho 4,45 gam hợp chất hữu cơ X (C₃H₇O₂N) phản ứng hoàn toàn với dung dịch NaOH vừa đủ, đun nóng được 4,85 gam muối khan. Công thức cấu tạo của X là:

A. H₂NCH₂COOCH₃ 

B. CH₂=CHCOONH₄ 

C. H₂NC₂H₄COOH 

D. H2NCOOC₂H₅ 

Read the following passage, and mark the letter (A, B, C or D) on your answer sheet to indicate the correct word (s) for each of the blanks.

From the seeds themselves to the machinery, fertilizers and pesticides -The Green Revolution regimen depends heavily on technology. One (4)                 , however , depends much(5)            on technology - organic farming . Many organic farmers use machinery, but (6)                 chemical fertilizers or pesticides .(7)                 chemical soil enriches , they use animal manure and plant part not used as food - natural, organic fertilizers that are clearly a renewable (8)                 .Organic farmers also use alternatives  (9)                 pesticides ; for example they many rely on natural predators of certain insect pets.(10)                    the need arises ; they can buy the eggs and larvae of these natural predators and introduce them into their crop fields . They use(11)                 techniques to control pests as well , like planting certain crops together because one crop repels the other’s pests . Organic farmers do not need a lot of land ; (12)                        ,organic farming is perfectly (13)                        to small farm and is relatively inexpensive .Finally , many organic farmers’ average yields compare favorably with other farmers’ yields.

Điền vào ô 9

A . from

B. to

C. of

  for

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