Please resubmit your question as it is unclear as to what someone would be saying maybe for. Thank you.
When someone says congratulations to you, or when someone congratulates you, say, "Thank you".
You clarify something for someone. For example, you could say, "Can you clarify this for me?"
write to someone is the correct word although many people say write someone
It would be more correct to say, someone who.
Just say no.
say that you meant to say that to someone else or say that your friend sent it as a joke.
don't say anything and if they ask you about it then say yes
The word gesundheit is an expression someone might say after you sneeze. You simply say "Thank you"
I say "Hello."
thank you
say hello
Someone would say "ow" becasue they got hurt.