“they are books”——它们是书。
将原句改为反问句为：
Aren't they books?——它们不是书吗？
将陈述句“they are books”改为反问句的步骤是:
1. 将句子的时态改为一般现在时的单数形式,谓语动词用"are"。
2. 将句子的词序调整为将助动词放到主语之前。
3. 在句子结尾添加反问词“aren't they”。
按照这些步骤,原句变为反问句的结果是:
Aren't they books?
句子的意思变为“它们不是书吗?”。
将一个陈述句改写成反问句的主要方法是:
1. 助动词置于主语之前
2. 句尾添加反问词,如aren't they, didn't you等。
反问句的构成如下：
1. 将陈述句中的助动词(be动词、情态动词、have等)置于主语之前。
例如：You are a student. → Are you a student?
2. 如果陈述句中没有助动词，需要添加情态动词do/does/did来构成反问句。
例如：You study English. → Do you study English?
3. 句末添加反问词，如aren't， didn't， doesn't等。
例如：You like swimming. → Don't you like swimming?
4. 如果陈述句是肯定句，反问句使用否定形式;如果陈述句是否定句，反问句使用肯定形式。
例如：You went there. → Didn't you go there?
You didn't see him. → Did you see him?
5. 反问词后的词序不变。
例如：You bought a car， didn't you?
综上，构成英语反问句的主要方法是将助动词置前、添加反问词并转换肯定否定形式。反问句用于寻求对陈述句的确认。