tThe [1] kKindle [2] is black

yYesterday [1] I saw a kKindle.  [2, 3]
I saw the black kKindle.  [2, 3]
tThe [1] kKindle [2] is black.  [3] 
I like the black kKindle.  [2, 3]

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[1] Every sentence starts with a capital letter (an "upper case" letter).

[2] Every "proper noun" starts with a capital letter.  The most common examples of a proper noun are a person's name, a company's name, and a product's name. For example:

"My name is Song. I like Apple products. My favorite product is my Kindle."

[3] Every sentence ends with a full stop ('.'), exclamation mark ('!'), or question mark ('?').

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Yesterday I saw a Kindle.
I saw the black Kindle.
The Kindle is black.
I like the black Kindle.