Although "lie detectors" are widely used by governments, police departments and businesses
That is the theory, but psychologists have found that lie detectors are simply not【C14】______. Since most physical changes are the same across【C15】______emotions, lie detectors cannot tell【C16】______you are feeling angry, nervous or excited.【C17】______people may be tense and nervous【C18】______the whole procedure. They may react physiologically to a certain word("bank")not because they robbed it, but because they recently used a bad check. In either【C19】______, the machine will record a "lie" .
On the other hand, some practiced liars can lie【C20】______hesitation, so the reverse mistake is also common.
【C1】
A.fixed
B.designed
C.known
D.produced