______(7)
A.vocational
B.educational       
C.official    
D.mutual

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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
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 ot her 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.
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

Read the passage carefully, then choose the best answer for each question.
THE DISEASE DETECTIVE
Six children were in the hospital. They were very sick, but the doctors didn't know what to do. They called Dr. Richard Besser, an expert on strange illnesses.  Dr. Besser knew just what to do.
Finding a Cause
First, Dr. Besser needed to find the cause of the illness. He used a microscope to look for germs like bacteria in the children's bodies. Dr. Besser found that all the children had a strain of the bacteria E. coli. Then he looked at the bacteria's DNA. The DNA showed him that this strain of E. coli was dangerous to humans.
Where Did It Come From?
Dr. Besser knew E. coli could move from animals to humans. Perhaps the children had touched animals that carried the bacteria? Besser found other E. coli cases in the area where the children lived. But it wasn't enough.
Besser then made a list of what the sick children had eaten. They had all eaten cheese, apple juice, and fish. He then made a list of what healthy children in the area had eaten, and compared his lists. They had eaten the cheese and fish, but not the apple juice.
Case Closed
Besser went to where the apple juice was made. He saw that there were animals around the apple trees, and he saw the workers using dirty apples that had fallen on the ground. More importantly, he saw that the apples were not washed before the juice was made, and that the juice was not heated. Doing these things would kill the bacteria. Besser then knew it was the apple juice that made the children sick.
Besser's E. coli case has a happy ending. The children got better. And what Besser learned that day now helps keep others safe.
Who does “they” refer to?
A.the sick children
B.the healthy children
C.both the sick and the healthy children
D.neither the sick nor the healthy children