He became ________ his weaknesses and tried to overcome them.[ ]

A. fond of  

B. aware of

C. proud of  

D. sure of

起重机上采用的齿轮联轴器是（）联轴器的一种，用以适应零部件的安装与调整。

A、刚性

B、弹性

C、塑性

D、脆性