I'd like to ask what "cross the lines" means in the sentence:
We had thus both bravely crossed the lines of our academic expertise and ended in presenting a classical example of synergism: the combined results of our individual paths.
My guess is as follows: 'cross the lines' means act beyond the limits of one's expertise.
A good idiom.
Meaning:Cross the lines:from being acceptable to being unacceptable.
Does it mean from being acceptable to being more acceptable?Or sarcasm.
Well.Let's wait for others' response.