Answer:
1. Miriam está estudiando para cirujana.
2. Tú estás mandando un mensaje por tu teléfono inteligente.
3. Nosotros estamos saliendo de vacaciones para Costa Rica.
4. Yo estoy cumpliendo con mi trabajo.
Explanation:
Identifying the narrator and the time that a sentence indicates is the first step that must be taken. this is very important to be able to logically conjugate the verbs, and that these have concordance with what is being expressed