Question

there is actopus in my aquarium (a , an)
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Answer 1

Answer:

a is used in consonents and an is used in vovels

Answer 2

Answer:

There is an octopus in my aquarium.

Explanation:

Octopus sound starts with o, which is a vowel sound. An is always used with a vowel sound. This is too make sure that an is not always used with all vowels, it all depends on the sound. So, pronunciation is important.