Now, use your pocketknife to touch the mica and see what will happen.现在你用小刀去触及岩石中的云母,看看会产生什么现象.It could not pass through material impervious to water such as mica.它不能通过云母这样的不透水的物质.To this class of substance belong mica, ...
刚好在450英尺的等高线之下有3个缓坡。There were three moderate climbs to just below the 450 feet contour.等高线是用等间距图解描述构造形态的.Contours are graphic expressions with uniform spacing depicting a structure's character.正射摄影象片一般不带像地图所表示的等高线....