Several colleagues are having tea and chatting at Xiao Wang's house  They discussed what kind of tea they were drinking  Xiao Liu said, it's not Longjing, it's not Biluochun  Xiao Zhao said, it's not Longjing, it's oolong tea  Xiao Li said, it's not oolong tea, it's Longjing tea
Finally, Xiao Wang confirmed that one of the three was completely right, one was only half right, and the other was completely wrong
Xiao Liu's judgment is absolutely correct. The tea they drink is oolong tea.