你变换一下大小写

不行啊，试过了。怎么回事呢？

mao si shi xi la zi mu li de 10, kan zhe bu xiang x.
For example,
y = money spend in supermarket
x = discount voucher you got from different supermarket each year
T= time period(year)
i = pid (people)
K = which supermarket
Hoping helpful