Uncertainty spreads through our lives so thoroughly that it dominates our language，Our everyday speech is made up in large part of words like probably, many, soon,great,little.What do these words mean? 
Such verbal imprecision is not necessarily to be criticized. Indeed, it has a value Just because it allows uw to express judgments when a precise quantitative statement is out of the question.
We have been trying to pin down by experiments what people meari by these expressions in specific contexts, and how the meanings change with age. For instance,a subject is told "There are many trees in the park" and is asked to say what number the word may mean to him. Or a child is invited to take "some" sweets from a bowl and we then count how many he has taken. We compare the number he takes when he is alone with the number when one or more other children are present and are to take some sweets after him, or with the number he takes when told to give
“some" sweets to another child.
First, we find that the number depends, of course, on the items involved. To most people some friends means about five, while some trees means about twenty. However, unrelated areas sometimes show parallel values. For instance, the language of probability seems to mean about the same thing in predictions about the weather and about politics: the expression is certain to( rain,or be elected)signifies to the average person about a 70 percent chance; is likely to, about a 60 percent chance; probably will, about 55 percent.
Secondly, the size of the population of items influences the value assigned to an expression.Thus, if we tell a subject to take "a few" or“a lot of" glass balls from a box, he will take me if the box contains a large number of glass balls than if it has a small number, But not proportionately more: if we increase the number of glass balls eight times, the subject takes only half as large a percentage of the total.
Thirdly, there is a marked change with age. Among children between six and fourteen years old, the older the child, the fewer glass balls, he will take. But the difference between a lot and a few widens with age. This age effect is so consistent that it might be used as a test of intelligence.
51. What's the right attitude towards the words like probably, any and soon ?
A. They are inaccurate and we should avoid them.
B. They are necessary since we cannot be always precise.
C. They should be criticized because there are too many of them.
D. Their value is not yet clear since we don't know their meaning.
52. Why do we do experiments with the words many and some?
A. To prove that people are insensitive to these words.
B. To prove that the words dominate our everyday speech.
C. To find out how the meanings vary with age and contexts.
D. To find out whether the words can mean a precise quantity.
53. Which of the following expressions means a larger chance in weather broadcast?
A. Possible.   B. Probable.   C. Be likely to.  D. Be certain to.
54. Which of the following is similar to the underlined word signifies in its meaning?
A. makes    B. means     C. predicts    D. indicates
55. Which of the following can be the best title for the passage?
A. Uncertainty in the Language Use.
B. How to Use Language in an Uncertain Way
C.Uncertain Words and their Use in Specific Contexts
D. Experiments on Relationship between Uncertainty and Language Use