Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 23 to 27.

                                                                The Microscope

         One of the most important inventions in the development of science and medicine was the microscope. It was (23) ........... the principle that light could be “refracted” or bent, by a glass lens. It was soon discovered that tiny objects could be magnified (24) ........... size when viewed through a glass lens that had been ground and polished in a specific (25) ........... Although the principle was known to the Chinese as early as 1000 A.D, it was not until the 13th and 14th centuries in Europe (26) ........... it was put to practical use in the form of eyeglasses.

          In Europe the first microscope was invented by brothers Zacharias and Hans Janssen, two Dutch eyeglass-makers, around 1590. They built a “compound” microscope, so called because of its two lenses. The most significant development and use of the microscope during this period, however, belongs to another Dutch optician, Antonie van Leeuwenhoek. Bom in Delft, Holland, he became skilled at (27) ........... very sharp and accurate magnifying lenses.

Điền vào số (23)

A. based upon  

B. based by      

C. based in  

D. based at

- Em hãy tìm trên hình 28.1 các vùng núi cao, các cao nguyên bad an, các đồng bằng trẻ, phạm vị thềm lục địa. Nhận xét về sự phân bố và hướng nghiêng của chúng?

Hỗn hợp X gồm Mg, MgO, Ca và CaO. Hòa tan 10,72 gam X vào dung dịch HCl vừa đủ, thu được 3,248 lít khí (đktc) và dung dịch Y. Trong Y có 12,35 gam MgCl₂ và m gam CaCl₂. Giá trị m là

A. 13,32.

B. 33,3.

C. 15,54.

D. 19,98.

mk có phần tự luận . bạn có lấy không?

Câu nào sau đây là đúng?

A. Hợp chất CH₃CH₂OH là ancol etylic

B. Ancol là hợp chất hữu cơ trong phân tử nhóm -OH

C. Hợp chất C₆H₅CH₂OH là phenol

D. Tất cả đều đúng