The correct verb form is "leo." Therefore, the sentence rewritten with the correct conjugation would be: "Yo leo la carta."
You can place in the blank just about any infinitive verb or verb phrase appropriate to the context:
A Jorge le gusta tararear en la clase de inglés: Jorge (George) likes to hum in English class.
A Jorge le gusta bocetar en la clase de inglés: Jorge (George) likes to draw in English class.
As a verb phrase:
A Jorge le gusta tomar notas en la clase de inglés: Jorge (George) likes to take notes in English class.
***OBSERVATION: Placement of a subject noun after "gustar" is done all the time (A Jorge le gustan los huevos fritos--Jorge likes fried eggs), but the prepostion "en" presents a problem for one intending to use a subject noun in the instant phrase. If one were to say, for example, Jorge likes the teacher in the English class, the proposition would become "de": A Jorge le gusta la profesora/el profesor de la clase de inglés.
