Every profession，every art，and every science has its technical vocabulary. Its function is partly to name things or processes which can not be described in ordinary English．Such special terms are necessary in technical discussion of any kind．Being universally understood by the specialists of the particular science or art，these terms have the exactness of a mathematical formula（公式）．Besides，they save time, for it is much more convenient to name a process than to describe it． 
Different occupations，however，differ widely in the character of their special vocabularies．In trades and handicrafts，and other professions，like farming and fishery，that have occupied great numbers of men in the past，the technical vocabulary is very old．It consists largely of native words, or borrowed words that have worked themselves into the very fibre of our language．As a consequence, though highly technical in many particulars，these vocabularies are more familiar in sound；and more generally understood，than most other technicalities．
Yet every profession still possesses a large body of technical terms that remain extremely unfamiliar, even to educated speech．And the amount has been much increased in the last fifty years．New terms are invented with the greatest freedom，and abandoned unconcernedly when they have served their turn．Most of the new inventions of words and expressions are restricted to special discussions, and seldom get into general conversation．
Yet no profession is，nowadays，as all professions once were，a closed association．Specialists in different fields share ideas and associate freely with each other. Furthermore, what is called “popular science” familiarizes everybody with modern views and recent discoveries. Any important experiment, though made in a remote lab, is at once reported in the newspaper, and everybody is soon talking about it—as in the case of the Roentgen rays and wordless telegraph. Thus our common speech is always taking up new technical terms and making them commonplace.
67．Technical terms are created so            .
A．specialists may communicate more easily
B．people may enjoy varieties of occupations
C．people may save time in everyday discussions
D．specialists may well accept mathematical formulas
68．The writer lists wireless telegraph as an example to show special words      .
A．should represent popular science
B．may become part of common speech
C．should be restricted to scientific fields
D．may be considered great inventions of man
69．What can we infer from the passage?
A．Nonteehnical words may be replaced.
B．Media helps to popularize special terms.
C．Various professionals exchange their terms.
D．Educated people know most technical terms.