供需

gōng xū supply and demand

的

de of; ~'s (possessive particle); (used after an attribute); (used to form a nominal expression); (used at the end of a declarative sentence for emphasis)

dí really and truly

dì aim; clear

dī see 的士[di1 shi4]

概念

gài niàn concept; idea; CL:個|个[ge4]

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