what's the most difficult train to catch?

what's the most difficult train to catch? what's the most diffcult train to catch? what's the best most difficult to learn what is the most difficult key to turn? What is the most difficult product sell to chinese 4.We haven’t ___ time to catch the train now.A .adequate B.s 1.We have not ( ) time to catch the train now.A.adequate B.s It's difficult to find the train station without his help.【改 What kind of the passengers are the most difficult to serve what's the most difficult problem do you have met in your pa we want to catch the first train to England she was -----late to catch the train to London