1.face在该对话中用作动词，意思是“朝向，面向”

eg. His office faces the garden.
他的办公室面对着花园。

2.at one's service意思是“听……吩咐，随时准备为……效劳”

eg. If you need any help, I and my car are at your service.
如果您需要什么帮助的话，我和我的车随时为您效劳。

3.free of charge 免费

eg. The department store delivers free of charge.
这家百货商店免费送货。

eg. The conversation is encrypted and, while in the network, free of charge.
谈话内容经过加密处理，而且在网内是免费的。