I can't play now, can you come back later?

Mike said, "I like grape soda".

can i used these as sentences

The first is called a run-on because it's really two sentences that are run together. This is correct:

I can't play now. Can you come back later?

The second sentence is fine, but put the period before the ending quotation marks, not after them.

thanks

You're welcome!

Yes, both of these can be considered as sentences.

The first sentence, "I can't play now, can you come back later?", is a complete sentence. It expresses a complete thought and contains a subject ("I") and a verb ("can't play"). It also includes additional information about the time ("now") and a question directed to the listener ("can you come back later?").

The second sentence, "Mike said, 'I like grape soda'," is also a complete sentence. It reports or quotes what Mike said, and it includes a subject ("Mike"), a reporting verb ("said"), and a direct quotation enclosed in quotation marks ("I like grape soda").

Both sentences are grammatically correct and can stand alone as independent thoughts or statements.