Identify one African empire and the impact they had on trade networks during the 1200 to 1450 time period.

Acquiring english is a way of learning where you learn english by birth, this includes listening to your parents, brothers and sisters and on the whole learning it from the environment around you while mastering standard english need qualified institutes and teachers who make certain programs and syllabus to you master the standard english. this also can include a long session of academic studies before you can master the standard english.standard english is necessary for literary works, official usage and writing materials for standardized publications or when someone needs to speak publicly. in most cases the employers of a company also demand and like the use of standard english from their employees. 

Ibelieve it is entry b.