The old man came ________ to the railway station, only ________ the train was slowly pulling out of the station.
My father and his teacher talked for about an hour of things and persons ______ they remembered at the school.
They have to explain ______ us the reason _____ their doing so.
Hand in hand with reading, Dave ____ the habit of making notes.
In the past few years, Chinese scientists ________ great success in the field of space flight.
History is _______ a subject which only lets us know something in history..