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 .

`1.`  Mary last wore that dress when she left school

`2.` Although revenues are very low last year, the company spent a lot of money on expanison.

`3.` Tuan asked Lan how often he went to the English club.

`4.`  If I were free today, I could go on a picnic