Can you use four movement bricks on one NXT? [duplicate]

Question

Possible Duplicate:
How can I use more than three motors with one NXT brick?

I want to make a tank out but it needs 4 movement bricks but I only have one NXT. Here are the parts:

1. It can move and that takes up two motion bricks so it can turn, move forwards and backwards.
2. It uses one movement brick for the gun.
3. it uses one movement brick because it will have a hatch that can open so that it can collect the balls that it has already shot so I don't need to get them manually.