a difficult or impossible task Taking a selfie with the Eiffel tower turns out to be a mission impossible, believe me! 相信我，在埃菲尔铁塔上拍照是一项不可能的任务！ Sometimes it feels like mission impossible to keep the children's toys neat and tidy. 有时候，要使孩子的玩具保持整齐整齐似乎是不可能的任务。