不充足。
因为毕业感谢信是对于毕业阶段的人们表达感谢之情的一种方式，需要用英文进行书写。
然而，80字的篇幅非常有限，难以充分表达感谢之情和对于帮助的真挚感激。
在有限的字数内，很难准确表达自己的感激之情和对于帮助的具体描述。
因此，80字的篇幅对于毕业感谢信来说是不充足的。
如果能够有更多的字数，将能够更好地表达感谢之情，并且对于帮助的具体描述和感激之情进行更充分的延伸。
以下是一篇英文版的万能感谢信，供您参考：
Dear [Recipient],
I am writing to express my sincere gratitude for [specific act of kindness or service performed]. Your thoughtfulness and kindness have made a huge impact on [describe the positive outcome of the act].
It is a pleasure to work with someone who possesses such qualities as [describe the recipient's qualities]. Your [recipient's profession/title] is a testament to your [describe the recipient's professionalism/skill], and I have no doubt that your [specific act of kindness or service performed] was done with the same level of excellence.
Please know that your efforts have not gone unnoticed. I have [describe the positive outcome of the act] and will continue to [describe how the recipient's act will be repaid or recognized].
Thank you again for everything. It is a pleasure to work with you.
Best Regards,
[Your Name]
