| 例句 |
closed booksnounpl. of closed book something hard to understand or explainthe couple's unorthodox marriage is definitely a closed book to those outside of the relationship conundrums, enigmas, head-scratchers, mysteries, mystifications, puzzlements, puzzles, riddles, secrets, whys brainteasers, cases, challenges, knots, matters, perplexities, posers, problems, stumpers, troubles |