Expressing and Responding to Sympathy

What is sympathy? How to express sympathy? Sympathy is feeling for someone without specifically understanding what they're feeling. When we want to express our simpathy in English, we can use the following phrases

Giving Sympathy:
-I'm sorry to hear that.
-I'd like to express my deepest condolences.
-I'm awfully sorry about ...
-How terrible/awfull for you !
-Oh, how awfull !
-Oh, dear !
-Poor you !
-I know how's you feeling ...
-I hope your trouble and now.

Responding to Sympathy:
- Thank you for your sympathy.
- It was nothing, etc.