In German, we have the expression "Mut zur Lücke", in English something like "courage to have a gap" - a knowledge gap. It is used between students, when they skip to learn something for an exam.

It's more the hope that this topic will be not part of the exam or test. So it is some kind of taking a calculated risk. The reasons can be diverse. Normally caused by the inability to understand or simply running out of time. Laziness or carelessness also play a roll.

When someone says this, she/he stops learning (of a certain topic) and accept the risk that it maybe ask in a test. Then of course she/he "know her/his limits", but this is secondary. She/he is brave / has nerve to have a knowledge gap.

Is there a similar expression in Chinese? I even could not found a translation for "knowledge gap" in Chinese.