To make matters worse, the tree that was standing near the bus stop was suddenly blown down by the wind.

blown 是动词 blow 的过去分词形式，blow 的意思是"吹、刮（风）"。 down 是副词，表示"向下"的方向。 blown down 这个短语表示"被风吹倒"，描述树木或其他物体因强风而倒下。