One of the ingredients in the cake was a cup of nondairy whipped topping.
Your question is itself a sentence which uses the word "could".
A kerchief is a cloth tied loosely around the neck, to keep away dust and dirt from the neck. A handkerchief does the same for the hands and cuffs. Cowboys of the Wild West wore kerchiefs, and pulled them up their faces when not wishing to be identified.
A sentence using the word Water tight could be "Is this seal watertight?" .
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An example of a sentence with are could be:"We are very happy that you could come to our party."
A Sentence using the word Gate Is: i went to open the gate so i could take my dogs for a walk .
A sentence using the word admit could be this, "The man on trial did not want to admit he was wrong."
Such a sentence could take some time to come up with.
Your spelling could use improvement.
I could not hear what you said.
The word "mirth" is a noun meaning merriment, joy, or laughter. An example of a sentence using the word is: The children could not hold back their mirth at the carnival.
I am not writing a sentence using that word.