Present simple and Continuous (D)
She is reading a book. = Ella ESTÁ LEYENDO un libro.
Ella LEE un libro.
However, if you want to describe routines, habits or facts you have to use the present simple tense only. For example:
They always watch a movie together = Ellos siempre VEN una película juntos.
You would also choose the Present Simple tense if you want to use a verb that describes mental/emotional states (Pienso, Siento, Creo), possessions (Tengo), sense perceptions (Huele bien! = It smells good!), and other existing states (Parece, existe, cuesta, pesa, etc.)
This activity is for the student to develop the habit of conjugating verbs correctly depending on whether they want to make use of the present simple or the present continuous tense.