limiting grade

例句：

1. 1. The movie is rated R for mature content.
   这部电影因内容成人不宜而被评为R级。
2. 2. The government has implemented a system to limit the number of cars on the road.
   政府实施了一个系统来限制道路上的汽车数量。
3. 3. The book is classified as a "limiting grade" due to its explicit sexual content.
   由于其明显的性内容，这本书被归类为“限制级”。