Đốt cháy hoàn toàn 9,1 gam hỗn hợp E gồm hai axit cacboxylic X, Y (M_X < M_Y), thu được 4,48 lít khí CO₂ (đktc) và 2,7 gam H₂O. Phần trăm khối lượng oxi trong phân tử Y là

A. 53,33%.

B. 71,11%.

C. 49,45%.

D. 69,57%.

Read  the following  passage and mark the letter A, B, C on your answer sheet to indicate the correct answer to each of the questions.

The art world

One of the major problems in the art world is how to distinguish and promote an artist. In effect, a market must be created for an artist to be successful. The practice of signing and    numbering individual prints was introduced by James Abbott McNeill Whistler, the nineteenth - century artist best known for the painting of his mother, called “Arrangement in Grey and Black”, but known to most of us as “ Whistler’s Mother”. Whistler’s brother - in - law, Sir Francis Seymour Haden, a less well - known artist, had speculated that collectors might find prints more attractive if they knew  that they were only a limited number of copies produced. By signing the work in pencil, an artist could guarantee and personalize each print.

As soon as Whistler and Haden began the practice of signing and numbering  their prints, their work began to increase in value. When other artists noticed that the signed prints commanded higher prices, they began copying the procedure.

Although most prints are signed on the right - hand side in the margin below the image, the placement of the signature is a matter of personal choice. Indeed, prints have been signed within the image, in any of the margins, or even on the reverse side of the print. Wherever the artist elects to sign it, a signed print is still valued above an unsigned one, even in the same edition.

Where in the passage does the author indicate where an artist’s signature might be found on a work?

A. Lines 14-15

B. Lines 6-7

C. Lines 9-10  

D. Lines 11-13

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

PHOTOSYNTHESIS

Almost all living things ultimately get their energy from the sun. In a process called photosynthesis, plants, algae, and some other organisms capture the sun's energy and use it to make simple sugars such as glucose. Most other organisms use these organic molecules as a source of energy. Organic materials contain a tremendous amount of energy. As food, they fuel our bodies and those of most other creatures. In such forms as oil, gas, and coal, they heat our homes, run our factories and power our cars.

Photosynthesis begins when solar energy is absorbed by chemicals called photosynthetic pigments that are contained within an organism. The most common photosynthetic pigment is chlorophyll. The bright green color characteristic of plants is caused by it. Most algae have additional pigments that may mask the green chlorophyll. Because of these pigments, algae may be not only green but brown, red, blue or even black.

In a series of enzyme-controlled reactions, the solar energy captured by chlorophyll and other pigments is used to make simple sugars, with carbon dioxide and water as the raw materials. Carbon dioxide is one of very few carbon- containing molecules not considered to be organic compounds. Photosynthesis then converts carbon from an inorganic to an organic form. This is called carbon fixation. In this process, the solar energy that was absorbed by chlorophyll is stored as chemical energy in the form of simple sugars like glucose. The glucose is then used to make other organic compounds. In addition, photosynthesis produces oxygen gas. All the oxygen gas on earth, both in the atmosphere we breathe and in the ocean, was produced by photosynthetic organisms. Photosynthesis constantly replenishes the earth's oxygen supply.

Organisms that are capable of photosynthesis can obtain all the energy they need from sunlight and do not need to eat. They are called autotrophs. Plants are the most familiar autotrophs on land. In the ocean, algae and bacteria are the most important autotrophs. Many organisms cannot produce their own food and must obtain energy by eating organic matter. These are called heterotrophs.

Advances in Photosynthesis and Respiration, Hardback.1990.

The word “replenishes” in the third paragraph is closest in meaning to ______.

A. renews

B. refines

C. refills 

D. regulates

Mark the letter A, B, C or D on your answer sheet to indicate the correct sentence that best combines each pair of sentences in the following questions.

Our products are environmentally-friendly. We package all of them in recyclable materials.

A. Packing our products in recyclable materials, we make them environmentally-friendly. 

B. Our products are packed in recycled materials to be environmentally-friendly. 

C. Packed in recyclable materials, our products were environmentally-friendly. 

D. The recyclable package of our products make them look environmentally-friendly.