She is not as good at sports as【 her】 sister .原句可以变为：She is not good at sports while her sister is.里面含有固定短语：be good at sth:善于、擅长于某事.因此,不能变为你所给的其他形式.祝你开心如意...老大，为何不能改成 She is not as good as her sister at sports. ？不是as… as…吗？as good as he sisiter像她姐姐一样好。好在哪里？——at sports,at sports来修饰good难道不对吗？抱歉！回答时重点看的是你给的第二种形式。She is not as good as her sister at sports你是对的！改成个形式完全可以哦！