Final answer:
In most cases, a green light at a crossroad does not allow for a left turn. However, a green arrow signal can be displayed along with the green light to indicate that a left turn is permitted.
Step-by-step explanation:
The question is about whether you can take a left turn at a crossroad that has a green light on. In most cases, a green light indicates that you are allowed to proceed straight or make a right turn, but not a left turn. However, there are instances where a green arrow signal may be displayed along with the green light, which specifically allows you to make a left turn. The presence of a green arrow signal usually means that oncoming traffic has a red light, ensuring that it is safe to make the left turn.