“Anton” means “opposite”, the term “antonymy” is used for “oppositeness of meaning”; words that are in opposition are antonyms. Antonyms classified on the basis of semantic contrast. There are four types of antonyms.（2 points）(1) Contraries/Gradable Antonyms: Contraries display semantic contrast, e.g. rich－poor, etc. All contraries are gradable words. According to Quirk, intensifiers or downplayers can be used in between to show the gradability, e.g. poor → hard up → well-to-do → well-off → comfortably wealthy → pretty bounty → rich;（1 point） (2) Complementaries/Non-gradable Antonyms: Complementaries represent a type of binary semantic contrast which admits no gradability between the items, and usually cannot take any adv. modifiers, e.g.male/female, boy/girl, alive/dead（1 point）; (3) Conversives are two-way contrasts that are interdependent. (4) According to Crystal(1980: 91), conversives are in such a relationship, found especially in the definition of reciprocal social roles, spatial relationships and so on. There is an interdependence of meaning, such that one member of the pair presupposes the other member, e.g. husband/wife, parent/child, up/down.（1 point）(4) Semantic Incompatiables denote multi-semantic contrast, like north, south, east, west; spring, summer, autumn and winter. (1 point)