变位
形容词,比较级 (Adjective, comparative): tougher
形容词,最高级 (Adjective, superlative): toughest
形容词 (Adjective): tough
名词,复数 (Noun, plural): toughs
名词,单数或不可数 (Noun, singular or mass): tough
动词,过去时 (Verb, past tense): toughed
动词,动名词或现在分词 (Verb, gerund or present participle): toughing
动词,第三人称单数现在时 (Verb, 3rd person singular present): toughs
动词,原形 (Verb, base form): tough
动词,非第三人称单数现在时 (Verb, non-3rd person singular present): tough