U and iu don't rhyme. In Chinese Pinyin, U is pronounced like Wu and Xu. In hanyu pinyin, iu sounds like You, Qiu Yaoren, etc. Obviously, the former does not rhyme with the latter. Rhymes, rhymes. "When writing rhymes, such as poems, songs and fu, using rhyming words at the end of sentences or couplets is called rhyme. Poetry rhymes, which makes the work sound harmonious, easy to recite and remember, and has the beauty of rhythm and timbre.