When others help you, you'd better thank them. What are the polite expressions?

If it is a small favor between classmates, you can say: thank you! Thank you, haha; Colleagues can say: thank you, thank you for your hard work. I'll treat you to dinner another day. Thank you very much

Just show your true thoughts and don't cater to them.

Because a familiar person, knowing your personality, will understand your mind. With this heart, even a simple thank you is enough to make him (her) feel; Unfamiliar people, too much performance will make others feel uncomfortable.

Don't be modest, that is, don't overdo it, don't lower yourself to compare with each other. A little help may be something that others can do conveniently. A thank you is enough. Don't deliberately raise each other's role, which is not good for people and themselves.