In1863thefirstunde的精選

問題詳情：  閱讀下面短文，在空白處填入1個適當的單詞或括號內單詞的正確形式。   In1863thefirstundergroundpassengerrailwayintheworldopenedinLondon.Itranforjustundersevenkilometersandallowedpeopletoavoid...