原句“He does not his homework on Sunday”是一个陈述句，意思是“他周日不做他的家庭作业”。要将其改为否定句，可以在句子中加入否定词“not”，并修正动词形式。可能的否定句有：
1. He does not not do his homework on Sunday.（双重否定句，意思是“他周日做他的家庭作业”）
2. He does his homework on Sunday.（去掉否定词，意思是“他周日做他的家庭作业”）
你要根据上下文和语境选择适合的否定句，以确保表达准确并符合语言逻辑。
He does not his homework on Sunday的否定句
因为是一般现在时第三人称单数的形式，所以要变成He doesn't do his homework on Sunday.原句少了实意动词fo。