I was about to leave home这里的about to是什么用法?

I was about to leave. he was about to leave when someone called him 为什么这里的leave不需要 I was just about to leave the house___the phone rang I was about to leave,___something occurred___attracted my at About To Make Me Leave Home 歌词 The carpenter was about to leave. ()Yesterday morning I was just about to leave ___ to telepho I was about to leave when it began to rain可否与suddenly 连用 I was about to leave my office _____i was told that the pres I leave home at about a quarter to eight . 1.否定句 2.一般疑问句 be about to的用法 I was just about to leave the house___the phone rang(a)while