The author's main purpose in the passage is to ______.

A．an educated person would be expected to know most technical terms
B．everyone is interested in scientific findings
C．the average man often uses in his own vocabulary what was once technical language not meant for him
D．various professions and occupations often interchange their dialects and jargons

A．never last long
B．are considered artificial language speech
C．should be confined to scientific fields
D．may become part of common speech