切牙舌向移动1mm需要间隙（）
A.2.5mm
B.3mm
C.2mm
D.1mm
E.1.5mm
参考答案：C
. _________ is good for you going to bed early and getting up early.
A．It
B．As
C．This
D．That
零部件失效是机械出现故障的主要原因。
