gratter

In a sentence

• Je gratte la guitare chaque soir.

  I strum the guitar every evening.

  In this sentence, 'gratter' is used to describe the action of playing a stringed instrument by strumming.

• Il a dû gratter le mur pour enlever la vieille peinture.

  He had to scrape the wall to remove the old paint.

  Here, 'gratter' is used in the sense of scraping or scratching a surface.

• Je me suis gratté la tête en réfléchissant à la solution.

  I scratched my head while thinking about the solution.

  In this instance, 'gratter' means to scratch, referring to the act of moving one's fingernails over the skin.