A:a2>b2
B:ab>1
C:2a>2b
D:lg(a﹣b)>0
As more and more cars are produced and used, the emission from their exhaust pipes contains an even larger volume of ____ (poison) gas.
图是我国跳水队员为迎接北京08年奥运会而刻苦训练的情景,在她离开跳板向上运动到最高点的整个过程中,关于她的动能、重力势能以及它们之间的相互转化,下列说法中正确的是( )
You'd better face challenges bravely instead of ____ them.