open book片語KK [ˋopən bʊk] /ˈoʊpən bʊk/發音片語1坦率的人、一目了然的事He's an open book; you always know what he's thinking.他是個坦率的人,你永遠知道他在想什麼。2未定之事、未知After graduation, her future is still an open book.畢業之後,她的前途仍是未定之數。形容詞1可查閱書本的、開放式的Tomorrow's test is open-book, but you still need to prepare.明天的測驗可以翻書,但你還是得準備。