表达疑问(亦即发问)或请求的句子叫做疑问句。如以下的例子：
Is he a friend of your brother's?
(他是你哥哥的朋友吗?--发问)
Can you do this for me?
(你能替我做这件事吗?--请求)
疑问句的句末必须使用问号(Question mark)“?来标示问句的结束。
疑问句：可分为一般疑问句、特殊疑问句、选择疑问句、反意疑问句和否定疑问句。
1、 种类 特征 语调 举例 回答
一般疑问句 系+主+表+?
助动词+主+动+? 升调 Are you from London?
Do you speak Russian? 用yes, no回答
2、 特殊疑问句 疑问词+系+表+?
疑问词+助+主+动+? 降调
How are you feeling?
When will you get there? 直接回答，不用yes或no
3、 否定疑问句 系+not+主+表?
助+not+主+动+? 表示惊异用升调。赞叹、责难用降调 Aren't they beautiful?
Won't you come in for a minute?
4、 选择疑问句 一般问句：系+主+表+…or…?
助+主+动+…or…? Or前升调。Or后降调 Is he tall or short?
Does he stay home or go there? 直接回答问句中一个，不用yes, no
5、 特殊问句：疑问词+系+主+…or…? 第一部分用降调，第二部分or 前升调，or后降调 Which is bigger, the sun or the moon?
Who runs faster, Tom or Peter? 选一个答案，不用yes, no
反意疑问句 陈述部分肯定：陈述，助(系)+not+主? 陈述部分用降调，一问部分用升调 It is raining, isn't it?
You did it, didn't you? 答案肯定时用yes，否定时用no
陈述部分否定：否定陈述句，助(系)+主+? 如对陈述肯定，可用降调 It isn't fine, is it?
They haven't come, have they?