Boys and girls, please turn to Page _____ and look at the _____ picture.
A:Fifth; five
B:Five; five
C:Fifth; fifth
D:Five; fifth
有3张飞机票,2张火车票,分别放在五个相同的盒子中,小亮从中任取一个盒子决定出游方式,那么他乘飞机出游的概率是____.
下列关于催化剂的说法错误的是( )
已知方程3x-y-7=0,2x+3y=1,y=kx-9有公共解,则k的值是( )