Very close, but not quite correct. "Could you lend me a newspaper to read if you have finished reading it." or "Could I borrow a newspaper to read if you have finished reading it." "Lend" and "borrow" work together; they are similar to "give" and "receive."

No, you would say "Can I borrow the newspaper if you have finished reading it?"

in general anyone speak English will understand it clearly. it seems good.

Hi there, What a wonderful sentence! Very rich in language and grammar. Yes the second half of the sentence "if you have finished reading it" is accurate and sounds great! In the first half however you've mixed up borrow and lend. Imagine you give me a pen to use for an hour. I borrow the pen. You lend the pen. You should also put the verb after the clause with lend and borrow. Eg: can you lend me a pen to use this lesson? I can lend you a tissue to blow your nose if you need one? May I borrow your car to drive to the station? So the sentence should be: could you lend me your newspaper (to read), if you've finished reading it? The reason I put 'to read' in brackets is because you don't really need it in this sentence, what else would you do with a newspaper? It doesn't need to be specified. I hope this information helps! Best wishes, Katherine