Itisnotdecided________theconferencewillbeheld.
C
A 什么 B 哪一个 C 什么时候 D (无词义)
Iwaswritingareportlastnight;________Iwouldnothavestayeduplate.
Theothertimingsystembelongsinourinternalclocks，which，left________，wouldtiethebodytoa25-hourrhythm.
Childrenhaveanatural________abouttheworldaroundthem.
Lyingundertheskull,thehumanbraincontainsanaverageoftenbillionnervecellscalled______.
Ifyouarewalkingawayfromaclocktower，youwillhearthetickingoftheclockfadetoapoint________itcannotbeheard.