下列有关金属的说法中不正确的是( ) A．纯铁比生铁的抗腐蚀性强 B．青铜、不锈钢、硬铝都是合金 C．铝在空气中耐腐蚀，所以铝是不活泼金属 D．人
AIDS is said__________the biggest health to people in that area over the past few years. A.that is B.to be C.that it has been D.to have been
Beijing's broadened ban on smoking in public places took effect Thursday, adding force to the effort to hold a smoke-free Olympics. The new rules extend existing anti-smoking regulations to more place
如图,是一个由5个大小相同的小正方体组成的立体图形,它的左视图是
This _____news made us happy.（惊人）
国史学家爱德华·卡尔在《历史是什么》一书中把史学说成是“历史学家跟他的事实之间相互作用的连续不断的过程，是现在跟过去之间的永无止境的问
若关于x的一元二次方程(a＋1)x2－ax＋a2－1＝0有一个根为0，则a＝______。
