They set off for London just after nine

They set off for London just after nine we set off for London just after ten.这句话的时态是什么,为什么? They looked for that set of keys just now. After resting in sydney for a few weeks,Chichester set off o set off on \set off for\set off doing 意义的差别 把They looked for that set of keys just now改为被动语态 start off for 与 set off for,有什么区别? start for,start out for,start off for,set out for,set off fo depart for 和set off的区别 They set off in search of the lost child.翻译 She took the nine o'clock _____(fly) to London just now They went to London () just over five months.