Present simple describes routines and states: Linh washes the dishes every evening. Present continuous describes temporary activity now: She is revising now, so her brother is washing them tonight. Add -s for third-person singular in the simple; use am/is/are + -ing in the continuous. Know, understand and want normally describe states, not current actions.
Topic preview: I think teenagers should share suitable housework because it teaches responsibility. For example, preparing vegetables helps a teenager appreciate the work behind a meal. However, heavy lifting and hot oil need adult supervision. I would begin with a short, safe task and adjust it during exams. Sharing does not mean dividing every job into identical pieces; it means agreeing on a fair contribution.