We must ______ that the experiment is controlled as rigidly as possible.
A、assureA
暂无解析
________fromtheoccasionallatenightparty,ourneighborsareveryquiet.
Becareful,_______you'llfalldown.
SinceWilliamhadbeenseriouslyillforseveralmonths,hisparentswereworriedabout________toreturntoschoolfull-time.
Inthefuture,more______shouldbeplacedontheeducationoftheyoung.
It________asashocktorealizethatIwasnotaloneintheroom.
