to be unprepared for sth
+ announcement, response对…没有防备
I was totally unprepared for the announcement the next day.我对第二天的通告完全没有心理准备。
+ weather, climate对…措手不及
Students from hot countries are often unprepared for the British climate.来自热带国家的学生往往对英国的气候毫无准备。