Final answer:
When passing a semi-truck, return to your lane once you can see the front of the truck in your rearview mirror.
Step-by-step explanation:
When passing a semi-truck, it is important to return to your lane safely and in a timely manner. The exact timing will depend on various factors such as the speed of your vehicle, the speed of the truck, and the distance between the two vehicles. As a general rule, you should return to your lane once you can see the front of the truck in your rearview mirror. This ensures that you have enough clearance and reduces the risk of a collision.