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.