1. Feminine singular nouns in the present tense:
* Example: La casa esta limpia. (The house is clean.)
* Example: La comida esta deliciosa. (The food is delicious.)
2. Feminine singular nouns in the present progressive tense:
* Example: Ella esta comiendo. (She is eating.)
* Example: La niña esta jugando. (The girl is playing.)
3. Feminine singular nouns as the subject of the verb "estar"
* Example: La computadora esta en la mesa. (The computer is on the table.)
* Example: La fiesta esta en la noche. (The party is at night.)
In short, "esta" is used with feminine singular nouns in the present tense and present progressive tense, and when "estar" is the verb.
Important: "Esta" is also used as a demonstrative adjective, meaning "this" or "this one".
* Example: Esta camisa es muy bonita. (This shirt is very pretty.)
However, in this case, "esta" is not related to the verb, but rather to the noun.