实行 (shíxíng) is a verb meaning 'to implement,' 'to carry out,' or 'to put into practice.' It is used for policies, plans, systems, or measures that are officially enacted. It is common in news, government documents, and formal writing.
学校从下学期开始实行新的考试制度。
xuéxiào cóng xià xuéqī kāishǐ shíxíng xīn de kǎoshì zhìdù.
The school will implement a new exam system starting next semester.
这项政策已经在全国范围内实行了。
zhè xiàng zhèngcè yǐjīng zài quánguó fànwéi nèi shíxíng le.
This policy has already been implemented nationwide.
公司决定实行弹性工作时间。
gōngsī juédìng shíxíng tánxìng gōngzuò shíjiān.
The company decided to implement flexible working hours.