vosotros, vosotras— you (informal or familiar plural; the first form refers to a group of males or males and females, while the second form refers to females only; this pronoun is seldom used in most parts of Latin America) ustedes— you (formal plural) ellos, ellas— they (the first ...
to create a situation where one thing will happen dependent on another. This is a very important structure to know how to use, because what you will find is that you talk about imaginary scenarios more than you think!