“气之根”指的是( )
A．肝B．心C．脾D．肺E．肾
参考答案：D
淬火钢的硬度由马氏体中的含碳量及（）的数量来决定。
The good thing about children is that they ________ very easily to new environments.[ ]
A．adapt
B．appeal
C．attach
D．apply
