Nowadays,food safety has become the________of the government as well as the society.
A:advantage
B:focus
C:step
D:anger
—Did you see Tom at the party?
—No, he by the time I got there.
如图,在Rt△ABC中,AB⊥AC,AD是斜边上的高,DE⊥AC,DF⊥AB,垂足分别为E,F,则图中与∠C(∠C除外)相等的角的个数是( )
雷锋说:“人的生命是有限的,可是为人民服务是无限的,我要把有限的生命投入到无限的为人民服务之中去。”请结合课文谈谈你对这句话的理解。