There is only one book of this kind left here, I wonder if you still want to buy____.
__________ in the mountains for a week, the two students were finally saved by the local police.
When different cultures, we often pay attention only to the differences without noticing the similarities.
Unless ___ to speak,you should remain silent at the conference.
When I came back, I found my clothes , on the bed.
We should take different measures different conditions and different occasions.