Conditionals are used to express both real, likely and unreal situations. As a result, tenses used with them are not flat; they change. That is why the difference between ‘If I arrive’ and ‘If I had ...
A handy list of links to resources for teaching tenses Stage 4: Talking about the weather. Grammar Tip: Simple and continuous forms of the present tense. Stage 6: Lost property. Grammar Tip: Simple ...