Children are      to meet with setbacks as they grow up, so their parents don’t have to worry about it.

A．reasonable

B．stable

C．bound

D．skilful

下列关于关节的叙述，错误的是（　　）

A．能活动的骨连接

B．由关节头和关节窝构成

C．关节囊外的韧带使关节更牢固

D．关节软骨和滑液使关节更加灵活