Question

Teachers have to constantly update their knowledge in order to maintain thei

Answer 1

Teachers have to constantly update their knowledge in order to maintain their【competence】.
翻译：教师们必须不断地更新他们的知识以保持他们能够胜任工作的能力。
或
为了保持能够胜任工作的能力，教师们必须不断地更新他们的知识。
翻译难点：
update 更新；使合乎潮流；使现代化
maintain 保持；保存；维持；持续；使继续
competence资格；能力；胜任，称职
祝你学习进步，时时开心！O(∩_∩)O~~

Answer 2

Teachers have to constantly update their knowledge in order to maintain their (competance).
教师们必须不断充实自己的知识才能保持胜任工作。