The term 'of course' is often used to express agreement or understanding, and the crossword solutions provided are all variations of this phrase. The three-letter solutions are 'YES, ' 'natch, ' 'AHA, ' 'doi, ' and 'duh, ' while the four-letter solutions are 'isee' and 'SURE.' The five-letter solution is 'natch, ' and the six-letter solutions are 'SURELY' and 'whyyes.' The seven-letter solutions are 'thatsit' and 'wellyes, ' and the eight-letter solution is 'tobesure.' The nine-letter solutions are 'CERTAINLY, ' 'NATURALLY, ' 'surething, ' 'yesindeed, ' and the ten-letter solutions are 'byallmeans' and 'DEFINITELY.' Finally, the fifteen-letter solution is 'withoutquestion.' All of these solutions can be used to express agreement or understanding in response to a statement.