The fireman couldn’t __________ what the dark thing was through the heavy smoke.
––Why didn’t you come to the party?––I had meant _____, but something unexpected happened.
We should discuss the plan _____ before we work it out.
Mom used only half of the money, the rest of which ______ saved for other purposes.
As he reached _____ back door, Jack saw _____ strange sight.
Between the two parts of the concert is an interval, ______ the audience can buy ice-cream.