1、give the green light
开绿灯，批准 ，相当于agree
2、give sb the green light
We are ready to build a great bridge over the river. We are just waiting for the municipal government to give us the green light.
我们已做好了在河上建一座大桥的准备，现在正等待市政府的批准。
3、give sb the green light to-v
Mother gave us the green light to go on the camping trip.
母亲准许我们野营旅行。