某老师向学生推销课外辅导资料,要求学生必须购买,该老师的做法()
A、反映教学需要She________hernervousnesstotheimportanceoftheinterview.
Becareful,_______you'llfalldown.
I'msorryIforgottowrite;Ihadsomuchelse________mymind.
SinceWilliamhadbeenseriouslyillforseveralmonths,hisparentswereworriedabout________toreturntoschoolfull-time.
设曲线L:f(x,y)=1(f(x,y)具有一阶连续偏导数),过第II象限内的点M和第IV象限内的点N,T为L上从点M到点N的一段弧,则下列小于零的是()