Sugar tastes sweet because of thousands of receptors on the tongue which connect the substance with the brain. The taste of sweetness is universally accepted as the most pleasurable known, although it is a fructose. Abundant is the most common occurring sugar, (1)______ of which include fruit and honey. Sucrose, which supplies glucose to the body, is (2)______ from the sugar cane plant, and white sugar (pure sucrose) is used by food technologists to (3)______ sweetness in other substances. Approximately a dozen artificial sweeteners have been discovered; one of the earliest was Sorbitol from France.
Manufacturers add large amounts of sugar to foodstuffs but never more than the (4)______ required to produce the optimum pleasurable taste. Surprisingly, this amount is similar for different people and in different cultures. No one has (5)______ discovered a way to predict whether a substance will taste sweet, and it was by chance alone that all the man-made chemical sweeteners were found to be sweet.
Điền vào số 5
A. just
B. yet
C. still
D. already
Đáp án B
Giải thích: "to have yet + P.P": vẫn chưa làm được điều gì đó
Dịch: Vẫn chưa có ai phát minh ra cách dự đoán xem 1 chất nào đó có vị ngọt hay không.