i got to the office early that day,____ the 7:30 train

题目

i got to the office early that day,____ the 7:30 train
为什么用having caught而不是to catch

答案

做非谓语时to do 为了（表目的,有将要的意思）
而这句句子是过去时态,是表结果,所以用having caught