Of the seven days in a week, Saturday is said to be the most popular __________ for a wedding in some countries. 

It is widely accepted that animals learn to do things because their certain acts lead to _______.

Don’t try to persuade your boss; he won’t have the _______of employing me — a fresh student.

The new safety regulations were agreed on after _____ with the work-force.

In the _______ of proof, the police could not take action against the man.