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...
He was intent on the job he was doing.他专心致志于正在做的工作.She behaved foolishly but with good intent.她表现得很愚蠢,不过用心却是好的.A merchant is intent on making money.商人热衷于赚钱....