Play a big role (in something) phrase
The adjectives "key" and "important" can substitute for the adjective "big".
If someone "plays a big role in something", he/she gets involved in a situation and has a significant influence on it.
Regular exercise and a balanced diet play a big role in a healthy lifestyle.
Kristine has played a big role in devising new strategy for her agency.
Parents are said to play a big role in forming a child's personalities.
The method of creating a mind map for each lesson had been playing a big role in my school days.
The verb "play" should be conjugated according to its tense.
People tend to like forbidden or illegal things just because they are forbidden or illegal.
He must have believed that stolen fruit is the sweetest, and he, therefore, cheated on his partner.