沿铝(A1)单晶的方向拉伸，使其发生塑性变形，请确定：
参考答案：
解析：当F点转到F’点时，发生双滑移。双滑移系统为：
―____ go out for a picnic with us this afternoon?
―I’d like to, but I’ll be busy preparing for the test.
A．Do you feel like
B．Would you like
C．Why not
D．What about
机床床身一般选用（）材料
A、HT200
B、KTH350—10
C、QT500—05
