—Many students don't know how to____ stress and become worried.
—I think they should ask their parents for help.
A:deal with
B:get on
C:care for
M、N为两块水平放置的平行金属板,距平行板右端L处有竖直屏,平行板长、板间距均为L,板间电压恒定。一带电粒子(重力不计)以平行于板的初速度v0沿两板中线进入电场,粒子在屏上的落点距O点的距离为L2,当分布均匀的大量上述粒子均以平行于板的初速度v0从MN板左端各位置进入电场(忽略粒子间作用力),下列结论正确的是( )+
下图所示为苏联某一时期社会结构的前后变化,它集中反映了( )