closed heater

例句：

1. 1. The closed heater keeps the room warm in winter.
   关闭的加热器在冬天保持房间温暖。
2. 2. The closed heater is a popular choice for heating homes during cold weather.
   关闭的加热器是寒冷天气中加热房屋的热门选择。
3. 3. The closed heater is easy to use and requires minimal maintenance.
   关闭的加热器易于使用且维护需求最小。