单项选择题
Some of the musical pieces for（）Isadora Duncan choreographed dances were waltzes and mazurkas by Chopin.
A．whom B．that C．which D．what
单项选择题 No plant can possibly exist on the moon because there is no water,（）is indispensable to life.
单项选择题 I hope that the little（）I've been able to do has been of some use.
单项选择题 He is regarded by all as a genius,（）the important discovery was made.
