很简单啊。举个最简单的例子youcanfindtheanswer.(转换为否定句)=youcan'tfindtheanswer.(转换为一般疑问句)=canyoufindtheanswer?(否定疑问句)=can'tyoufindtheanswer?其实就是将句子中be动词/动词转化为否定形式。或者添加否定词语。例如:youcanneverfindtheanswer.