Hi.
I saw the following sentence:
"They're a horrible colour."
[STRIKE]Doesn't[/STRIKE] Shouldn't this sentence [STRIKE]have to[/STRIKE] be "They have a horrible colour no full stop here"?
Welcome to the forum. :hi:
Please note my changes above.
You must end every sentence with an appropriate punctuation mark, even a sentence as short as "Hi". In future, though, you don't need to include a greeting in your posts. Just go straight ahead with your question.
As Rover said, you must provide the source and author of anything you quote on the forum, so that information is missing after "I saw the following sentence".
When you quote a full sentence inside a question, don't use the closing punctuation mark of the quoted sentence. The question mark at the end of the sentence serves as the closing punctuation.