Learn Spanish (Latin America): Leo ese libro para ser muy profesional. - I am reading that book to be very professional.

In this sentence, para expresses the purpose of an action. It translates to 'in order to.' Whenever you want to say 'in order to do something,' you use para followed by an infinitive verb (like ser).

Why is the verb ser in its infinitive form instead of being conjugated?

After prepositions like para, verbs stay in their infinitive (unconjugated) form. Since para already gives us the meaning 'in order to,' you just add the action word (ser, meaning 'to be') directly after it.

Why do we use ser here instead of estar?

We use ser because being professional is considered a core characteristic or part of someone's identity, rather than a temporary state or mood. Professions and defining personal traits always use ser.

The translation says 'I am reading,' but leo means 'I read.' Why not use estoy leyendo?

In Spanish, the simple present tense (like leo) is frequently used to describe actions happening right now. While you could say estoy leyendo, using the simple present is perfectly natural and common for 'I am reading.'