两者均可表示“感激”，但有区别：即 appreciate 的宾语是事或事物，而 thank 的宾语必须是人。如：

　　我们对他道谢后就离开了。

　　误：We appreciated him and left.

　　正：We thanked him and left.

　　我们感谢你的好意。

　　误：We thank your kindness.

　　正：We appreciate your kindness. (比较：Thank you for your kindness.)