1. They didn't let him go because they didn't invited him
$\longrightarrow$ He wasn't invited so they didn't let him go
2. They didn't make the beds after getting up this morning
$\longrightarrow$ The beds weren't made after getting up this morning.
3. She didn't win the prize but her friend did
$\longrightarrow$ The prize wan't won by her by her friend did
4. I did not tell them the truth
$\longrightarrow$ They werenot' told the truth
5. Did you give them the books that I bought?
$\longrightarrow$ Were the books that I bought, given them?
10. Did he send the letter for me?
$\longrightarrow$ Was the letter sent for me?