Answer:
1. I started going to the gym last month.
R- cuando empezaste a ir al gimnasio?
2. I saw her yesterday
R-cuando viste a karla?
3.That one is yellow.
R- viste alguna amarilla?
4.That's twelve dollars
R- cuanto es?
5.Diego lent me his motorcycle
R- quien te prestó la motocicleta?