He kept looking at her, wondering whether he _____ her somewhere.
--- Shall we take the 10:20 train? --- No. If we took that train, we too late.
--- I had thought he would be nervous in this speech competition, but he turned out to be calm. --- He quite enough preparation for it.
Don’t give up regardless of difficulty and failure, you’ll never achieve your goals.
--- Have you got any books on English grammar? I’d like to borrow . --- Yes, here you are. But you must return it by Friday.
David got a higher grade in the final exam, for, you see, he made mistakes.