v wear off or die downv sink to a lower level or form a depressionv sink down or precipitatev descend into or as if into some soft substance or place
v. （土地）下陷（因在地下采矿）( subside的过去式和过去分词 ); 减弱; 下降至较低或正常水平; 一下子坐在椅子等上