grateful letter

Hello, I need to write a note to give of thanks for to my work colleagues. They are chinese people and a little bit older than me. So I want to write it in chinese and wothout without any mistakes. But I don`t know how to say in chinese following frases: (what do you mean)
It was great (nice) to work with you. 跟你们一起工作很开心。
Thank you for all of your helps. 谢谢你们所有的帮助。
Thank you for comprehension (understanding). 谢谢你们的理解
Thank you for give me a chance make available to work with you. 谢谢你们给我机会和你们一起工作。
You are were very kind. 你们很和善。
Thank you for all. 感谢所有人
I don`t forget this a learning experience (worthwhile experiment).
I won't forget this experience of learning.我不会忘记这个学习的经历。
It would be great if you can will help me ^_^

grateful letter

Hello, I need to write a note of thanks for my work colleagues. They are chinese people and a little bit older than me. So I want to write it in chinese and wothout mistakes. But I don`t know how to say in chinese following frases:
It was great (nice) to work with you.     跟你们合作是一件很愉快的事。
Thank you for all your help.           对于你们的帮助，我非常感谢。
Thank you for comprehension (understanding).    谢谢/感谢您们的理解
Thank you for make available to work with you.     感谢你们给了跟你们一起合作的机会。/感谢你们让我们一起合作成为可能。
You were very kind.      你们非常友善
Thank you for all.     感谢所有的一切
I don`t forget this a learning experience (worthwhile experiment).   我不会忘记这些学习经历（宝贵的实践）

It would be great if you will help me ^_^