1. clothes, cloth, clothing clothes统指各种衣服,谓语动词永远是复数, cloth指布,为不可数名词 clothing 服装的总称,指一件衣服用a piece of, an article of 2. amount, number amount后接不可数名词, number后接可数名词 eg:a number of students 3. sound, voice, noise sound自然界各种各样的声音,voice人的嗓音,noise噪音 eg:I hate the loud noise outside. 4. cause, reason cause 指造成某一事实或现象的直接原因,后接of sth./doing sth,reason用来解释某种现象或结果的理由,后接for sth./doing sth. eg:the reason for being late