The indefinite pronouns algún and ningún need to agree in gender (when possible) and in number with the noun they are substituting. Algo and alguien are not gender or number specific.

Revised: All students will develop their own lesson plans. Change point-of-view or use an indefinite pronoun. Original: A person's decision should be based on his or her career goals. Revised: Your ...

This sentence may be rewritten: few will visit this place. A sentence with an indefinite pronoun, like “nobody” at the beginning, leads a story to nothingness. It indicates the writer is not ...