“下陷”怎么读

“下陷”的英语可以翻译为：sag，undercut，sink，cave in，settle ...

床垫是否高低不平并且下陷？Is the mattress lumpy and saggy?那意味着整个房子正在下陷吗？Does that mean the whole house is subsiding?黑色的拎包由于装了各种形状的东西而中间下陷.The black reticule sagged under the weight of shapeless objects....