Here's why:
* "Through" has a unique vowel sound: The "ough" in "through" makes a distinct /u:/ sound, similar to the "oo" in "moon".
* "Ough" is unpredictable: The "ough" spelling has many different pronunciations in English, making it difficult to find words that rhyme with a specific "ough" sound.
Let me know if you'd like to try another rhyming challenge!