Apple.
voice, vowel, vocal
immediate
thrusts
When the first letter of the next word starts with a vowel or the letter H. But of course there are exceptions.... a humble opinion.
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A five letter word that starts with 'tha' is THANK.
Queer is a five letter word.
Snail.
Use "a" before a word that starts with a consonant sound, and use "an" before a word that starts with a vowel sound. For example, "a cat" (pronounced as kæt) and "an apple" (pronounced as əˈpl̩). Remember that it is based on the sound, not the actual letter.
apple
Beans
Organ