Asking for an explanation:
* "I heard you were sick. Why don't you come to work today?"
* "I heard a strange noise outside. Why don't you go check it out?"
Expressing surprise or curiosity:
* "I heard she got a promotion. Why, that's great news!"
* "I heard you're moving. Why are you leaving?"
Expressing disapproval or skepticism:
* "I heard you were arguing with your boss. Why would you do that?"
* "I heard you're going to invest in that company. Why, it seems risky."
Expressing sympathy or understanding:
* "I heard you lost your pet. Why don't you come over for dinner and we can talk about it."
* "I heard you're feeling down. Why don't we go for a walk?"
The specific meaning of "heard" and "why" will depend on the context of the sentence.