The report shows that we’re making some progress but ______ we need to make greater efforts.
A cook will be immediately fired if he is found _______ in the kitchen.
It is said that in Australia there is more land than the government knows _______.
The research is so designed that once _______ nothing can be done to change it.
Having a trip abroad is certainly good for the old couple, but it remains _______ whether they will enjoy it.
_______ such heavy pollution already, it may now be too late to clean up the river.