I would like to return the rental car.
我来还租的车。
May I get the keys and see some ID?
请把钥匙给我，并给我看你的证件，好吗？
Let's go outside and take a quick look at the car.
我们到外面去把车子检査一下吧。
I need to fill out a report on the return condition of the car.
我需要填一份车子“归还车况”的报告。
Make a note if you find any dents or scratches.
要是你找到任何划痕或刮伤，请注明一下。