PREP中一道PS求解

sfps01

原题是：For a finite sequence of nonzero numbers, the number of variations in sign is defined as the number of pairs of consecutive terms of the sequence for which the product of the two consecutive terms is negative. What's the number of variations in sign for the sequence 1, -3, 2, 5, -4, 6

A:1  B:2  C:3  D:4  E:5

小弟看不懂题意啊，猜得题意是求相邻两个数的乘积是负数的有几对，所以选了D，求各位大牛帮忙解答，多谢~

yxyqm

楼主理解的挺对的