Exercise 2. 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 questions.
Centuries ago, man discovered that removing moisture from food helped to preserve it,
and that the easiest way to do this was to expose the food to sun and wind. In this way
the North American Indians produced pemmican (dried meat ground into powder and
made into cakes), the Scandinavians made stockfish and the Arabs dried dates and
apricots.
All foods contain water - cabbage and other leaf vegetables contain as much as 93%
water, potatoes and other root vegetables 80%, lean meat 75% and fish anything from
80% to 60% depending on how fatty it is. If this water is removed, the activity of the
bacteria which cause food to go bad is checked.
Fruit is sun-dried in Asia Minor, Greece, Spain and other Mediterranean countries, and
also in California, South Africa and Australia. The methods used vary, but in general
the fruit is spread out on trays in drying yards in the hot sun. In order to prevent
darkening, pears, peaches and apricots are exposed to the fumes of burning sulphur
before drying. Plums for making prunes, and certain varieties of grapes for making
raisins and currants, are dipped in an alkaline solution in order to crack the skins of the
fruit slightly and remove their wax coating, so increasing the rate of drying.
Nowadays most foods are dried mechanically; the conventional method of such
dehydration is to put food in chambers through which hot air is blown at temperatures
of about 110°C at entry to about 45°C at exit. This is the usual method for drying such
things as vegetables, minced meat, and fish.
Liquids such as milk, coffee, tea, soups and eggs may be dried by pouring them over a
heated horizontal steel cylinder or by spraying them into a chamber through which a
current of hot air passes. In the first case, the dried material is scraped off the roller as a
thin film which is then broken up into small, though still relatively coarse flakes. In the
second process it falls to the bottom of the chamber as a fine powder. Where
recognizable pieces of meat and vegetables are required, as in soup, the ingredients are
dried separately and then mixed.
Dried foods take up less room and weigh less than the same food packed in cans or
frozen, and they do not need to be stored in special conditions. For these reasons they
are invaluable to climbers, explorers and soldiers in battle, who have little storage
space. They are also popular with housewives because it takes so little time to cook
them.
Question 9: What is the main idea of the passage?
A. Advantages of dried foods. B. Water: the main component of food.
Dẫn chứng/ Giải thích:………………………………………………………………….
C. Mechanization of drying foods. D. Different methods of drying foods.
Question 10: The phrase “do this” in the first paragraph mostly means ______.
A. expose foods to sun and wind B. remove moisture from foods
C. produce pemmican D. moisten foods
Dẫn chứng/ Giải thích:………………………………………………………………….
Question 11: The word “checked” in the second paragraph is closest in meaning to
_____.
A. reduced considerably B. put a tick
C. examined carefully D. motivated to develop
Dẫn chứng/ Giải thích:………………………………………………………………….
Question 12: In the process of drying certain kinds of fruits, sulphur fumes help
______.
A. remove their wax coating B. kill off bacteria
C. maintain their color D. crack their skin
Dẫn chứng/ Giải thích:………………………………………………………………….
Question 13: Nowadays the common method for drying vegetables and minced meat is
______.
A. spreading them out on trays in drying yards
B. dipping them in an alkaline solution
C. putting them in chambers and blowing hot air through
D. pouring them over a heated horizontal steel cylinder
Dẫn chứng/ Giải thích:………………………………………………………………….
Question 14: What does the word “which” in the fourth paragraph refer to?
A. Vegetables B. Foods C. Things D. Chambers
Dẫn chứng/ Giải thích:………………………………………………………………….
Question 15: The final product of the process of drying liquids that uses the first
method will be ______.
A. small flakes B. fine powder C. dried soup D. recognizable pieces
Dẫn chứng/ Giải thích:………………………………………………………………….
Loga
Sinh Học lớp 12
