将陈述句的主语放在句首，动词变为助动词do/does/did，并在句末加上问号，即可改为一般疑问句。

例如，陈述句 "She is a teacher." 改为一般疑问句为 "Is she a teacher?"要改为反问句，则在陈述句后加上简短的反问句，通常使用助动词do/does/did或情态动词。例如，陈述句 "You like pizza." 改为反问句为 "You like pizza, don't you?" 或者 "You do like pizza, right?"