在一定条件下,对于反应mA(g)+nB(g) cC(g)+dD(g),C物质的体积分数(C%)与温度、压强的关系如图所示,下列判断正确的是( ) A.ΔH<0 m+n>c+d B.ΔH<0 m+n<c+d C.ΔH>0 m+n>c+d D.ΔH>0 m+n<c+d 答案:B--Students should devote most of their time to studying rather than playing computer games. ---________. No pains, no gains.A.ExtremelyB.ActuallyC.ObviouslyD.Exactly