1.Mary hasn't worn that dress since she left school
⇒Mary last wore that dress when she left school.
2. Despite the slippy road , they will drove very fast.
⇒Although the road was slippery, he drove his car today.
3. “ How often do you go to the English club?” Tuan asked Lan.
⇒Tuan asked Lan how often she went to the English club.
4. I can’t go on a picnic because I am not free today.
⇒If I were free today, I could go on a picnic .