谢谢大家的英语表达可以是：Thank you, everyone. 语气更强烈一点的可以用：thanks a million万分感谢；heartfelt thanks由衷的感谢。

例句示范：

Thank you everyone for your passionate participation and valuable feedback.
谢谢大家热烈的参与和宝贵的意见。

Thank you everyone for warm welcome!
谢谢大家的热烈欢迎！

Thank you everyone. Thank you very much.
谢谢大家，非常感谢你们！

Molly: I really appreciate it. Thanks a million.
莫莉：我真的很感激，多谢了。

Thanks a million. I really appreciate it.
万分感谢，真的是帮了我大忙啦。

Please accept my heartfelt thanks for your concern and generosity.
请接受我对你的关怀和慷慨的由衷谢意。

I also take this opportunity to all the teachers to express my heartfelt thanks and highest respect.
我也借此机会向全体教师表示衷心的感谢和崇高的敬意。