描述磁场中各点磁场强弱及方向的物理量是磁感应强度,符号是B,单位是韦伯。
参考答案:错
(2013·高考山东卷)It was ________ cold winter night and the moon was shining brightly across ________ night sky.
A.不填;a
B.a;the
C.the;a
D.the;不填
在金属切削机床的管理检查内容中,距操作者站立地面高度小于2m处有外露的传动部位,要检查防护罩、盖、栏等的完备、可靠性。()