Both clay and sandstone are unstable rock formations.黏土和砂岩都是不牢固的岩石构造。An aquifer is a water - bearing rock stratum such as sandstone and chalk.地下蓄水层是一些有水的岩石层,如沙岩和白垩岩.Houses in the area are built of sandstone.这个地区的房屋都是用砂岩建...
花园里万紫千红，鸟鸣嘤嘤。The gardens blazed with colour and throbbed with birdsong.鸟鸣报晓.The singing of the birds heralded in the day.鸟鸣声不时打破林中的寂静.Now and then a bird's song broke in upon the silence of the wood....