There was a time when a C meant average. The average GPA at four-year colleges and universities has risen from 2.52 in the 1950s to 3.11 in 2006. And according to Stuart Rojstaczer, a former Duke University professor and founder of GradeInflation.com, GPAs only keep rising. At some colleges, Rojstaczer says, over 50% of the grades given are A's.
Trench warfare was caused by an advance in defensive weaponry. The machine gun was too heavy to be used as a mobile weapon, and therefore was placed into a fixed position. Barbed and concertina wire was also heavily used.
A trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a wider gully, or ditch), and narrow compared with its length (as opposed to a simple hole). In geology, trenches are created as a result of erosion by rivers or by geological movement of tectonic plates. In the civil engineering field, trenches are often created to install underground infrastructure or utilities (such as gas mains, water mains or telephone lines), or later to access these installations. Trenches have also often been dug for military defensive purposes.