31. An allomorph is any of the variant forms of a morpheme as conditioned by position or adjoining sounds.
For example, the allomorphs “–ion/-tion/-sion/-ation”are the positional variants of the same suffix.
32. Derivation or affixation is a process of forming new words by addition of a word
element, such as a prefix, suffix or combining form to an already existing word.
Forexample, the word “unfair” is formed by adding the prefix “un-“ to the already existing word “fair”.
33.The meaning of a polysemous word is often determined by the linguistic context in which it appears, including the lexical, grammatical, and verbal context in its broad
sense. For instance, the verb make can be used in many different senses when it is combined with different lexical items, e.g.: The regulations were made (enacted) to
protect children. We made (had) a good lunch before leaving. The train was making(traveling at a speed of) 70 miles an hour.
34.The four commonest tendencies of the change of word meaning are:
1) Restriction of meaning/Specialization: a word of wide meaning acquires a narrower,
specialized sense which is applicable to only one of the objects it had previously
denoted. E.g. the word meat originally meant “food”, but now means “the flesh of
animals used as food, excluding fish and birds”.
2) Extension of meaning/Generalization: the widening of a word’s sense until it
covers much more than what it originally conveyed. E.g. the word bird meant a young
bird before, but now means “feathered creatures with two legs and two wings”.
3)Degeneration of meaning/Pejoration: Degeneration of meaning is a process
whereby words of good origin fall into ill reputation or non-affective words come to
be used in derogatory sense. E.g. “accident” once meant an occurance or an event, but
now it means only “bad occurance”.
4) Elevation of meaning/Amelioration: Elevation of meaning refers to the process by which words rise from humble beginning to positions of importance, or a word
meaning takes a turn for the better in the course of time. E.g. “minister” once meant a servant, it now means “a person at the head of a Department of State”.
35.Antonyms may be classified on the basis of semantic contrast or of morphological
structure. Semantically antonyms fall into three types:
1)Contraries/Contrary terms: they display a type of semantic contrast, illustrated by
such pairs as rich and poor; heavy and light; deep and shallow, etc. They are gradable
antonyms.
2)Complementaries/Contradictories: they represent a type of binary semantic
opposition. In this case, the contrast is absolute. Examples are: alive and dead,
married and single, present and absent. In this case, sb or sth is either A or B, there is
no compromise between.
3)Conversives/Relational opposites: another type of binary opposition as shown in
lend and borrow, husband and wife, employer and employee. In this case, the
relationship between the two words is interdependent, one member of the pair
presupposes the other member.
Antonyms can also be classified morphologically into root antonyms and derivational
antonyms. Words like deep/shallow, love/hate, up/down are root antonyms, for they
are words with different roots. Words like happy/unhappy, possible/impossible,
loyal/disloyal, code/decode, etc. are derivational antonyms, each pair has the same
root.
原文：http://www.cnblogs.com/hmeic/p/5100211.html