The letter 'r' is a very common consonant in English and frequently appears in words ending with 'e'. It often precedes the final 'e' or appears in common word structures. The pattern could fit words like "practice", "drainage", etc. Since we already have the vowels 'a' and 'e' identified, adding a high-frequency consonant like 'r' gives us the best chance of revealing more of the word structure.