将英文陈述句改为反问句的基本规则如下：

肯定句变反问句

在肯定句末尾添加疑问词（如isn't, aren't）+主语+助动词be，句尾标问号。例如：

- He is a teacher. → Isn't he a teacher？

- They are students. → Aren't they students？

否定句变反问句

在否定句末尾直接添加not，句尾标问号。例如：

- She isn't a teacher. → Isn't she a teacher？

特殊注意事项

- 若句子以be动词（am/is/are）开头，需将be动词提前至句首。例如：

- The cake tastes delicious. → Doesn't it taste delicious？

- 若句子中有实义动词，需借助助动词do/does/did将谓语提前。例如：

- The cat chased the mouse. → Did the cat chase the mouse？

补充说明

反问句常用于确认信息，如：

一般疑问句：Is this your book？

反问句： Isn't it your book？

通过以上规则，可灵活将陈述句转换为反问句，增强语言表达的互动性。