YDS CÜMLE ATMA / TEST 3 39. Soru

39.

- (I)We don't completely understand why people
or animals yawn. (II) It is widely assumed that
yawning occurs because we are tired or bored.
(III) Another theory is that we yawn because we
see someone else doing it. (IV) As a result,
when one yawns, his or her alertness is
heightened. (V) However, there isn't any hard
evidence to support these beliefs.