lower covert

例句：

1. 2.
   在军事上
2. 3.
   在艺术上
3. 1. The lower part of the building is used for storage.
   建筑物的较低部分用于存储。
4. 2. The artist lowered his voice to avoid being overheard.
   艺术家压低了声音以免被偷听。
5. 3.In the lower levels of the museum, there are exhibits about ancient history.
   博物馆的较低层有关于古代历史的展览。