二次函数y=ax2+bx+c(a≠0,a、b、c为常数)的图象如图,则方程ax2+bx+c=m有实数根的条件是____.
我当小裁判。
There is a zoo in our city. It's very big. In the zoo, there are many animals. Look, the birds are singing in the tree. A bear is riding(骑)a bike. A tiger is eating meat(肉). Two monkeys are climbing(爬)a tree. They are happy in the zoo.
阅读短文,判断正误。
反应4A(g)+3B(g)═2C(g)+D(g),2min后B的浓度减少0.6mol•L﹣1.对2min内反应速率的表示正确的是( )
下列各句中没有语病的一项是( )
每一位信仰伊斯兰教的成年人,在经济和身体条件允许的前提下,都把朝圣作为自己的一项宗教义务,他们朝拜的圣地是在