计算下列各题
—The difficult maths problem has been solved by Tom at last.
— Indeed; and the ___ way Tom worked out the problem impressed the teacher deeply.
黄帝之后过了很久，尧、舜、禹先后成为____的部落联盟首领。
如图所示是手影游戏，关于影子的形成原因，分析正确的是（ ）
