改为一般疑问句，并做肯定回答。 They had to work day and night. _

改为一般疑问句，并做肯定回答。
They had to work day and night.
___ they ___ ___ work day and night ?
___ , ___ ___.

Did they have to work day and night?
Yes, they did.

一般疑问句是疑问句的一种。它是指用yes或no来回答的句子。其结构是： 系动词be/助动词/情态动词＋主语＋其他成分? 1．将陈述句变为一般疑问句时，如句中有be 动词（am is are …）时，可直接将它们提至主语前。如主语为第一人称，应将其改为第二人称。如： i'm in class 2grade 1． → are you in class 2grade 1？ we're watching tv． → are you watching tv？ 2．陈述句中有情态动词（can may must …）时，也可直接将它们提至主语前，即可成为一般疑问句。如： he can swim now． → can he swim now？ the children may come with us． → may the children come with us？ 3．陈述句中只有一个实义动词作谓语且其时态为一般现在时，变为一般疑问句时要在句首加do或does 主语后的实义动词用原形。如： i like these animals． → do you like these animals？ she wants to go to the movies． → does she want to go to the movies？ 4．一般疑问句一般读升调(↑) 5．一般疑问句有时不用yes或 no 回答。如： are they in town now？ i think so. may i sit here？ certainly． does he like soccer？ sorry i don't know． 6. 一般疑问句的第一单词总是虚词,读的时候要读轻声。