Depends on the intersection. Usually you can, but you need to pull into the intersection and yield to the oncoming cars. The green arrow means that oncoming cars going straight have a red light, so you can easily go.
@Goated Ray The solid lights are for going straight. if it's red, you can't go straight. If it's green, you can. The arrow lights are a bit more complicated - if it's green, you can immediately turn left - oncoming traffic has a red light and you have the right of way. If it's yellow, the same is true, but that privilege is about to be taken away. If there's no turn light at all, but a solid green light is on, you can turn left, but you need to yield to oncoming traffic, because they have the right of way (this will usually be confirmed with a sign next to the light). Drivers often pull into the intersection when this happens, so they can make the turn easier.
