And

1. To suggest that one idea is chronologically sequential to another: "Tashonda sent in her applications and waited by the phone for a response." 
2. To suggest that one idea is the result of another: "Willie heard the weather report and promptly boarded up his house."
3. To suggest that one idea is in contrast to another (frequently replaced by but in this usage): "Juanita is brilliant and Shalimar has a pleasant personality.
4. To suggest an element of surprise (sometimes replaced by yet in this usage): "Hartford is a rich city and suffers from many symptoms of urban blight."
5. To suggest that one clause is dependent upon another, conditionally (usually the first clause is an imperative): "Use your credit cards frequently and you'll soon find yourself deep in debt."
6. To suggest a kind of "comment" on the first clause: "Charlie became addicted to gambling — and that surprised no one who knew him."