主语It was me that went downstairs when the window had to be shut
谓语going downstairs was what I did when the window had to be shut.
状语downstairs I went when the window had to be shut.
状语从句:not until the window had to be shut did I went downstairs
主语It was me that went downstairs when the window had to be shut
谓语going downstairs was what I did when the window had to be shut.
状语downstairs I went when the window had to be shut.
状语从句:not until the window had to be shut did I went downstairs