例如to+动词原形,短语,什么介语加形容词等等答:五)以f或fe结尾的变f为v再加es(s).如:knife-knives, wife-wives, half-halves, shelf-shelves, leaf-leaves, yourself-yourselves 六)单复数相同(不变的)有:fish, sheep, deer鹿子, Chinese, Japanese 七)一般只有复数,没有单数的有:people,pants, shorts, shoes, glasses, gloves, clothes, socks 八)单...