palavras = "nos, a, preste"
texto = "Ao nos resolver a esta tarefa, preste nos atenção nos seguintes a nos pontos:"
palavras_spl = palavras.lower().replace(',', '').split()
text_spl = texto.lower().split()
count = {p: text_spl.count(p) for p in palavras_spl if p in text_spl}
print(count) # {'preste': 1, 'a': 2, 'nos': 4}
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