Yo estoy en la universidad
Estoy is the conjugation of the verb estar for the first person singular in the simple present. We use the verb estar to indicate temporary states and locations. In this way, this verb stands for position, location, action, condition, and emotion. Here in this sentence, this verb stands for location, describing that I'm temporarily at the university.
La clase de anatomía es de cinco a siete
Es is the conjugation of the verb ser for the third person singular in the simple present. It is important to say that the simple present tense is used to talk about habitual actions or routines. This tense is also used to describe things that happen now or in the near future. On the other hand, we use the verb ser to talk about permanent or lasting attributes. In this way, this verb stands for descriptions, occupations, characteristics, time, origin and relationships. Here we use this verb as time, referring that a class will take place at a certain moment.
Mi hermano y su esposa vienen a cenar esta noche.
Vienen is the conjugation of the verb venir for the third person plural in the simple present. It is important to say since we didn't mention above that the simple present tense is used to talk about habitual actions or routines. This tense is also used to describe things that happen now or in the near future. So in this sentence, the simple present stands for something that will happen in the near future being tonight this point.
A las siete yo corro al supermercado
Corro is the conjugation of the verb correr for the first person singular in the simple present. Here in this sentence, the simple present also stands for something that will happen in the near future. Thus, I am going to the supermarket at seven o'clock
Tú tienes que regresar a casa antes de las siete
Tienes is the conjugation of the verb tener for the second person singular in the simple present. This is an important Spanish verb and means to possess, own, or hold. So in this sentence, you have to come back home before seven o'clock. So, it is obvious that the translation of this sentence would be:
- You have to come back home before seven o'clock
or
- You must come back home before seven o'clock
