`1.`
`→`Câu hỏi:What was Mary making for her grandmother?
`2. `
`→`Câu hỏi:When did he find the sliver coin?
`3.`
`→`Câu hỏi:What was you doing when I telephoned?
`4.`
`→`Câu hỏi:Who were they talking with?
`5.`
`→`Câu hỏi:What were the kids listening to when you saw them?
`6.`
`→`Câu hỏi:What was Peter doing while his wife was watering the trees?
`7.`
`→`Câu hỏi:Who was singing a folk song at this time yesterday?
`8.`
`→`Câu hỏi:What was Josh doing when he was hit by a motorbike?
