unpredictable; mys terious ? 投機(jī)事業(yè)就和出兵打仗一般，要抓得準(zhǔn)，干得快！又何況又有個～的老趙是對手方！ (茅盾《子夜》302)Speculation’s like fighting a battle—you must seize the bull by the horns,and move fast! Especially when you’re up against an unpredictable devil like Zhao Botao.