【单选题】从标有1,2,3,4,5,6,7,8,9的9张卡片中任取2张,那么这2张卡片数字之积为偶数的概率为
【简答题】Travel is to us in at least three ways. First, We can see many places with our own eyes. We can visit some famous cities and scenic spots(风景区). Second, we will meet people with different interests and...