1. To refer to something in general
2. To refer to something specific
3. With nouns in an abstract sense
4. With days of the week (except after ser)
5. To express the equivalent of "on saturdays"
6. With body parts and personal accessories
7. With titles (except when speaking directly to someone)
8. With last names to indicate the plural
9. With seasons (except after ser)
10. With languages (except after hablar, de, and en)
11. With dates
12. With street names
13. With meals
14. With weights and measurements with "a" or "an"
15. With certain places( jail, market, work, church, town, school)
16. With percentages
17. With fields of knowledge when referred to in a general sense
18. With infinatives used as nouns
19. With certain geographic names (la Argentina, el Brazil, el Canada, el Peru, los Estados Unidos, la Ameria latina/Central/del Sur
20. With oceans, rivers, seas |