Let’s start with zero conditional. When we want to talk about things that are always or generally true, we use the zero conditional. In this type of conditional we are not referring to one specific event. Look at the example. If you fly business class, you get amazing service. If in this sentence means every time. Every time you fly business class, you get amazing service. Now, let’s analyze the verb forms in the sentence. There is fly in the if clause, and get in the main clause. Both verbs are in the present simple.