Good Riddles

Question: You can call me a home, but I have no doors.
Someone lives inside me, but leaves when there's no more.

What am I?

Question: What single line can you add to the following statement to make it true?

5+5+5=550

Question: Which comes first, chicken or egg?

Question: If you have three apples and four oranges in one hand and four apples and three oranges in the other hand, what do you have?

Question: A person was born in 1940. Today is his 18th birthday.

How is that possible?