The public transport system in Beijing is very good now, so there _____be any difficulty in traveling around the city.
Fortunately we had a map, without _____ we would have got lost.
Two years later, her father disappeared, never to be _________ again.
We want to encourage the students ________ the teaching.
What he said was not relevant _________ the matter in hand.
Those _________ may leave the classroom now.