Thanks for the heads up 是人们最常用的表达方式。
这两个表达方式含义相同，都是用来感谢别人让他们知道现在或将来的一个事实或情况。"Thanks for the heads up"是更常见的口语表达。"Thanks for a heads up"不太常用，但在特定情况下可以根据上下文来使用。
Thanks for the heads-up, Earl.
Okay, thanks for the heads-up about the meeting.
Thanks for the heads-up last night, Janet. It gave me some time to plan my night.
Thanks for the heads up, Artie. See you at the softball game on Friday!
Sorry I missed your call, Mr. Coleman, but thanks for the heads-up.
Although it could be too late to change plans, thanks for the heads up.
Thanks for the heads up. I haven't had time to fix myself up.
Thanks for the heads up on the credit card usage--I didn't know I had spent so much!
Thanks for the heads-up, by the way.
Thanks for the heads-up on the eyewitness who saw the redhead.
"Thanks for the heads up," said the man, after his friend told him that he had jury duty the following week.
Thanks for giving me a heads up on this project.
Okay,** thanks for a heads** up regarding the house inspection.
Thanks for giving me a heads up last night, Janet.
Can I give you a heads up on what she is going to ask you?
Sorry, Steve, you didn't give me a heads up on this matter earlier.
Thank you for giving my mom a heads up about the family gathering in advance. I appreciate it.
I gave you a heads up but you didn't listen and jumped in the frozen lake anyway.
Thanks for a heads-up on any future plans we might make.