Who would you rather _____ your graduation ceremony tomorrow, your parents or friends?––All of them

People often have the belief ________a healthy environment and development cannot be possible at the same time, but this does not have to be true.[ ]

I have decided ________her for hermistake____ everyone makes mistakes in life.

When in contact with hot surfaces, the material can___________ poisonous gases.

Before I talked with ______ scientist, Ihad never met______ clever person like him.