Homophones are words identical only in( )but different in spelling and meaning as in son and sun.
【正确答案】：SOUND
【题目解析】：本题考查同音异形异义词。Homophones are words identical only in sound but different in spellig and meaning as in son and sun.同音异形异义词是读音相同但拼写和词义不同的词，比如son（儿子） and sun（太阳）。故答案为sound。
