L = [95.5,85,59]

print L[0]

print L[1]

print L[2]

print L[0],L[1],L[2]

他最后让你尝试l[3]就是让你看到如果越界会运行失败，去掉这行就能通过了

因为L[3]超出索引范围了，把这行屏蔽就可以运行正确

for x in [ 0,1,2,3,4,5,6,7,8,9]:

    for y in [ 0,1,2,3,4,5,6,7,8,9]:

        if x<y:                                                    #别忘了冒号

            print x*10+y;