sag subduction

例句：

1. 1. The boat sank slowly into the water.
   船慢慢地沉入水中。
2. 2. The fabric sags when it is wet.
   布料湿了会下垂。
3. 3. The car's suspension sags under heavy loads.
   汽车的悬挂系统在重载下会下垂。