Not until all the fish in the river died _________ how serious the pollution was.[ ]

With a lot of difficult problems ____, the newly-elected president is having a hard time.

One primary goal of UNESCO is to____modern knowledge society in which all people canparticipate in information and knowledge. [ ]

Daniel, don’t watch such horror films again.—Sorry,_________.

－Where is your mother－She _______ the supermarket to buy some food.