以下压力容器的破坏变形中，有显著塑性变形的是（）
A.韧性破裂
B.脆性破裂
C.疲劳破裂
D.应力腐蚀破裂
参考答案：A
With the development of modern agriculture and industry, ____ waste are created every day.
A．a large quantity of
B．large quantities of
C．a large number of
D．large numbers of
A．时刻t线圈中电流的瞬时值icosωt
B．线圈中电流的有效值I
C．线圈中电流的有效值I=
D．线圈消耗的电功率P
cosωt
