There are not enough teachers in the school, and in-service teachers ask for off-the-job training on their own. If they agree, it will affect the normal teaching work of the school, and the students in charge of teaching and their parents will not agree. For the requirements that directly affect the normal work of the unit, the unit can of course refuse. Or the applicant can come up with an effective solution to negotiate, or simply resign and go to training, and let the school solve it by itself, but the prognosis may be problematic.