Articles: a/an , the & no article

Fill in the blanks with the correct article: a/an , the or - (no article)

" My neighbours have __(1)____cat that climbs through my windows and terrorises my goldfish!I'm going to buy __(2)_____ dog next year"

"My neighbour is __(3)____ doctor. He keeps himself to himself. Once , my son got sick 😷 and I asked _(4)___doctor to come  and have a look and he said , " My office hours are from 8.00 until 14.00". Charming!"

" ____(5)People are funny!My neighbours here in ______(6) Birmingham have an apple 🍎 tree that hangs over my garden .Once some apples fell into my grass,and they came round to collect them!"

some extra samples:
https://www.thoughtco.com/article-use-in-english-quiz-4064229
Key exercise 1: 1. a, 2.a,3.a, 4. the,5. Zero article, 6.zero article.