可以用句号，也可以用逗号，还可以用冒号。
例句：
Thank you. Youve been a great help already.
谢谢你。你已经帮了很大的忙。
Thank you a thousand times， youre an angel.
千恩万谢了，你是个天使。
"Thank you doctor，" said the nurse with a simper.
“谢谢你，医生，”护士傻笑着说。
I'm perfectly capable of doing it myself， thank you.
谢谢，我完全有能力自己做。
Thank you:“You are kinds of you！”
谢谢你，您太好了！
感谢某人某事 thank sb of sth
比如：Thank you for your kind help
感谢某人做某事 thank sb for doing sth
比如 ： Thank you for helping me with my English
