When talking or writing about a play, should you refer to a specific part of the play only by the scene number and not the act number?

No you should refer to the scene and act number of the play so that everyone knows exactly what part you talking or writing about

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.