A week before the Big Ten meet①，Owens accidentally② fell down a flight of stairs③。

【专家解说】：A week before the Big Ten meet①，为时间状语 accidentally②方式状语, 可换成by accident 偶然地/不小心地 a flight of stairs③作介词down的宾语, down a flight of stairs 介词短语作地点状语. 句意: 在"大十运动会"前一周, 欧文斯不小心从一段楼梯上摔了下来.