There is also free access to one slot of quizlet with idioms from this book
https://quizlet.com/816910128
The object of to 'build upon' is something you already have that you can use to develop something else.
The simplest example is a house, e.g.
‘The house was built upon a foundation’
Usually, it's used with more abstract ideas
You can develop more advanced skills by building upon your knowledge
You can develop further by building upon the strengths that you already have.
'What makes you tick?'
When you ask yourself such a question, you're looking for the motives, reasons, causes, and inner driving force to explain why you act the way you do
I've never been able to understand what makes him tick.
I've always wondered what makes people like that tick.
