Grammar fix
a driving force
main impetus (figurative)
the person or thing that is most responsible for making something happen or for encouraging progress, especially in a project, movement, or change
Hear it in context
Notice where the phrase sounds natural.
- Her passion for education was the driving force behind the charity's success.work
- In my opinion, curiosity is often the driving force behind scientific discoveries, as it motivates researchers to keep exploring new ideas.IELTS speaking
Fix the pattern
Pattern: a/the driving force behind/for something
WrongShe was the driving force of the project.
RightShe was the driving force behind the project.
'The driving force BEHIND something', not 'of'.
Patterna/the driving force behind/for something
Use it right
Choose the version that sounds natural in speech.
'The driving force behind' is the natural fixed phrase; 'principal instigating agent' is made-up officialese.
Build natural chunks
Words that usually travel with it.
the driving force behindthe projectthe campaignchangethe company
Don't confuse it
Unlike 'the main reason', which simply explains why something happens, 'a driving force' suggests ongoing energy or motivation that makes things happen.