It is the general phenomenon of human society that there are always two kinds of people exist in either extremes , and they are the rich and the poor. As we know that they are quite different from each other, such as reputation in society, dwelling-house, asset, mood and behaviour, heritage, etc. Owing to all these factors, it is easy for us to define who is poor or vice versa. In general, the people who are rich will likely tend to be proud of themselves or even discrimination against the middle and the lower classes. Usually, majority of the rich are aggressive by holding bigger organizations or factories etc so as to be predominant in the society; while the poors are always being pressed for standard of living.
參考: Partly according to The Advanced Learner Dictionary of Current English with Chinese Translation by Oxford University Press in 1975