n.硬质地层；粘土层；砂砾层

Prices have reached(the) hardpan. 物价已经降到了最低点。

When small lakes dry up, they leave a salt crust or hardpan. 当小的湖泊干枯时候，它们留下盐壳或沙砾层。

Its uninviting surface is marked by mesas and buttes, and barren stretches of parched desert hardpan. 不起眼的表面有著台地与小尖山以及贫脊乾燥的沙质地基。

The various kinds of data-financial affair, human affairs and various files in work system are conserved in computer hardpan. 办公系统中各种重要数据如财务帐目、人事资料、各种档案等将保存在计算机的硬盘中。

The most important problems research had to solve were: (1). build-up and maintenance of soil fertility; (2). avoid soil hardpan and (3). control soil erosion. 研究要解决的最重要问题是：（1）积累和维持土壤肥力；（2）避免土壤硬磐；（3）控制土壤侵蚀。