2019-09-20 resentful / bitter / much / many

[shidenggui]

R: How are you doing tonight?
I: I have been coding for a while.
R: That's typical.
R: Do you realize that you and your colleagues are in the cutting-edge of the technology explosion.
I: Yes.
R: Do you realize your generation is part of the technology explosion. I was born after WW2. When I was a child, we said poor China, no technology. Now, the last twenty years, BOOM. Do you feel it? Do you understand it?
I: The economic economy of China is growing rapidly.

economy / economic / economics / economical

First I used economic, but the teacher corrected me. I should use the word economy. But what's the difference between these words?
economy: 经济
economic: 经济的，形容词
economics: 经济学
economical: “not requiring too much of something” (such as money, space, time, etc.), e.g. 节省的，话费不多的