Abeamoflightwillnotbendroundcornersunless________(make)todosowiththehelpofareflectingdevice

Theassociationis________toraisingfundstohelptheblind.

Humanbehaviorismostlyaproductoflearning________thebehaviorofanimalsdependsmainlyoninstinct.

SinceWilliamhadbeenseriouslyillforseveralmonths,hisparentswereworriedabout________toreturntoschoolfull-time.

中国民族资产阶级在社会主义革命时期的两面性是___________。