_____ is known to us all is that the old scientist, for _____ life was hard in the past, still works very hard in his eighties.
Not until the train pulled into the station that his suitcase was gone.
This is the best way ______ I have thought of ______ the problem.
However difficult you find to arrange your time, it will pay off in the long run.
Walter offered us a lift when he was leaving the office, but our work ______, we didn’t accept the offer.
ThejobprovedtobemuchmoredifficultthanI______.