Onecanfigureoutthemeaningof“airmail”tobe“mailbyair”byits______.
A、onomatopoeicmotivation
B、morphologicalmotivation
C、semanticmotivation
D、etymologicalmotivation
Hegraduatedfromcollege________hisparentsdivorced.
A、which
B、before
C、while
D、that
Theothertimingsystembelongsinourinternalclocks，which，left________，wouldtiethebodytoa25-hourrhythm.
A、behind
B、alone
C、out
D、aside
Johnhardlyspeakstoanybodyintheclass,________________?
Iwaswritingareportlastnight;________Iwouldnothavestayeduplate.
A、however
B、otherwise
C、therefore
D、furthermore