Помогите по английскому языку, 5 класс. Найти все артикли и объяснить почему они там...

Помогите по английскому языку, 5 класс. Найти все артикли и объяснить почему они там стоят!!! ПОМОГИТЕ ПОЖАЛУЙСТА


Mark Twain, the famous American writer, was well-known as a lecturer.Literary clubs often invited him to speak.Before one of his lectures a club member came to him and said: Twain, people say that you can tell very funny stories.I hope that during your lecture you will tell a story that will make my uncle laugh. He hasnt laughed for ten years. Ill do my best.Mark Twain said. When he began his lecture,Mark Twain noticed the club member.He was sitting in front of him with an old man who had a very sad face. Mark Twain began to tell jokes, one after another.I told long jokes and short jokes, new jokes and old jokes,Mark Twain told his friends.I told every joke l knew and soon everybody was laughing .Everybody- but not the old man.He was looking at me with cold, blue eyes.I couldnt make him laugh, and Itried again and again.But nothing helped,... After the lecture, the club member came to Mark Twain and said, Thank you,Mr Twain .I have never heard so many funny stories. They werent funny enough for your uncle, Mark Twain answered .He didnt even smile. I know, the man said.He hasnt laughed for ten years.But I didnt tell you that he hadnt heard anything for ten years.He is deaf.

The famous writer - потому что определённый предмет (писатель)
артикль а ставится тогда,когда существительное начинается на согласную.
артикль an ставится,когда существительное начинается на гласную.