To stay safe in the forest at night, we should try hard to keep the fire _______.
It is the interaction between people, rather than the events ___ occur in their lives, ____ is the main focus of social psychology.
—Will you join us in the party this Saturday evening? —If I ____ ,I would ;but I will have left for Japan on business by then.
He didn’t put the things ______ they belonged, for ______ reason he got his punishment.
How can you expect him to make any progress _____ you never give him a chance to have a try?
It is amazing that the little boy can swim ________the river ________100 meters in width.