Thank God, you finally arrived safely. You can never imagine how I worried about you when I was informed of the accident.

arrived 后 safely 是否正确？使用 safe 是否更佳？

【答】这里用副词或者形容词都是正确的。（1） ... you finally arrived safely.

这是副词作状语，修饰谓语动词。(2) ... you vere safe.= ... you finally arrived safe when you arrived.例如：Tom came home very tired. （汤姆回家时很疲倦。）= Tom was very tired when he came home .（摘自《刘毅英语语法宝典》p.191）