My students had to give answers to the following question: 'When you were younger, did people who knew you think that you would make the grade?'
Prior to setting them this task, we learnt that 'make the grade' means that you show evidence that your skills and knowledge are at the required level.
One of the answers I received is this: When I started studying at university I had to make the grade for the groupmates and teachers. Otherwise they could have build the wrong opinion concerning my knowledge.
Is it correct to use the expression 'to make the grade' with the preposition 'for', or is it better to use the preposition 'to'?
Frankly, I have never come across this expression being used this way.
Thank you in advance.
No, it's entirely unnatural.
You just "make the grade" without doing with for anyone or with anyone. Perhaps "in [someone]'s eyes" would work.
But it's a final result - not an opinion they form of you.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.