【单选题】The mother cried because _______.
A.
her son understood nothing for her life
B.
she was afraid she couldn't keep her new job
D.
the family burden proved too much for her
【单选题】The young mother walked off, leaving the little boy _____ in the room. [ ]
【单选题】It's very foolish _____ it?
【单选题】在相同条件下多次重复测量同一量时,出现大小、符号均无规律变化 的误差称为( ) 。
【单选题】It's very foolish of the commander to expose his men to _____ risks.
【单选题】如图所示,一个半径为 R 的导电圆环与一个轴向对称的发散磁场处处正交,环上各点的磁感应强度 B 大小相等、方向均与环面轴线方向成 θ 角 ( 环面轴线为竖直方向 ) 。若导电圆环上载有如图所示的恒定电流 I ,则下列说法中正确的是 ( ) 。
D.
导电圆环所受安培力的大小为 2π BIR sin θ
【单选题】The mother cried because ________________ .
A.
her son understood nothing of her life
B.
she was afraid she couldn’t keep her new job
D.
the family burden proved too much for her
【单选题】It's very foolish _____ it?