If You Drop an Apple, It'll Break

The if plus present simple part gives us a possible future situation. The other part is made with will plus an infinitive, without two and it as the result of thisossible future situation. It's sometimes difficult to choose between the zero and first conditional. If you're talking about a specific situation or a one off situation, the first conditional is probably best. For example, to describe a general situation that is true for everyone, we can use the zero conditional to say, if you sit in the sun too long, you get burned.