Oil - yielding organic matter is contained in the shales.在这些页岩里有产油的有机物质.Thus clays and shales tend to be impermeable.因此粘土和页岩就往往不透水.Sandstones are, as a rule , interbedded with shales.砂岩通常都与页岩互层.Alternating sandstones and...
A little porcupine made a house by the side of the river.小刺猬在小河边上造了一幢小房子.It is the Kookaburra ( Porcupine ) and Skunk Kingdoms that greet you today.今天是笑翠鸟 ( 豪猪 ) 和臭鼬王国向你们问候.One of the sharp hollow spines of a porcupine o...
These benches belong under the trees.这些长凳该放在树下.They broke asunder, sidling out of their benches, leaping them.他们忽然散开来, 有的侧身从凳子前挤出去, 有的从上面一跃而过.Large mining equipment cannot be operated on narrow benches.大型采矿设备不能在窄台阶上操作......