Explain how compounds differ from free phrases by using silkworm, green hand, and bad-mouth as examples.
【正确答案】：Compounds differ from free phrases in three aspects. 1)Phonetic features. In compounds the word stress usually occurs on the first element whereas in noun phrases the second element is generally stressed if there is only one stress. As in silkworm, the stress is on silk.
2)Semantic features. Compounds are different from free phrases in semantic unity. Every compound should express a single idea just as one word. For instance, a green hand is an 'inexperienced person", not a hand that is green in color.
3)Grammatical features. A compound tends to play a single grammatical role in sentence, for example, a verb, a noun, or an adjective. Bad-mouth used as a verb can take the third person singular-s and the past tense marker-ed
