Source: Dollars to Donuts..., Pete Zarria, Flickr
Knowing dramatic conventions and how they function is not just something to help you pass English tests. Knowing about monologues, soliloquies, and dramatic irony will add to your understanding and enjoyment of plays, both classic and modern.
The actors in a good play have to know how to be actors, and the audience members have to know how to be audience members. Knowing dramatic conventions is part of preparing yourself to be a first-rate audience member.
Source: IMG_5716, Ashley Marinaccio, Flickr