I________mytrainleftat5∶00p.m.an

I ________ my train left at 5∶00 p.m. and was disappointed when I arrived at 4∶50 p.m. and learnt that it had just left．I found later that I ________ an out-of-date timetable．A.thought; had usedB.have thought; had usedC.think; have been usingD.was thinking; was using