We know that the workers ____ all night but there is no other way. [ ]

33．When problems such as energy crisis, pollution and population explosion_________, people are asked to share the bitterness and endure the hardship with all the whole nation of the times．

e ______ the door, he found his keys were nowhere

The nature reserve is a good place _______ wildanimals ____ live ___.

The possibility of a murder _____, the police have set about looking for the clues to her suicide.