David was (in the barber's ) when the UFO arrived.
( where )( was )David when the UFO arrivied?
We were (listening to the teather carefully) when she came in.
( what )( were )you(doing )when she came in?
He swam(last Monday).
He (was )(swimming ) at four last Monday afternoon.
Tom Had a traffic accident yesterday.
A traffic accident( happened )( to )Tom yesterday.
Tom was always helping others in the past.
( was)Tom always ( helping )others in the past?