1 stumble (over/on sth) to hit your foot against sth when you are walking or running and almost fall over 绊脚；绊了一下

2 stumble (over/through sth) to make a mistake when you are speaking, playing music, etc （说话、演奏等时）犯错: The newsreader stumbled over the name of the Russian tennis player. 新闻读稿员说错了那个俄罗斯网球选手的名字。