appreciate和thank均可表示'感谢'，均为及物动词，但appreciate的宾语是事或物，而thank的宾语是人。
We greatly appreciate your help. 我们非常感谢你的帮助。
I would much appreciate it if you could do me that favor. 要是你能帮个忙，我将非常感谢。
Thank you so much for coming. 非常感谢你的光临。
比较
I thank your kindness to the full.
I appreciate your kindness to the full. 我十分感谢你的好意。
