MyGrandpahasasmallfarm改为否定句是My grandpa doesn't have a small farm.行为动词做谓语，一般现在时主语是第三人称单数，变否定句时，加入助动词，doesn't,原来的动词要还原。
My grandpa has a small farm.我的外公有一个小农场。My grandpa doesn't have a small farm.我的外公没有一个小农场。
