Using 'si' (if) with various tenses in french

Just like in English with 'if', French use 'si' to talk about things that might happen, would happen, or would have happened, dependent on another event happening. 

There are a few ways this can be formed.

Si + present event + present event

e.g. If you believe everything you see on the internet, you risk being a victim of fraud.

Si vous croyez tout que vouz voyez sur Internet, vous risquez de devenir victime de la fraude.

Si + present event + future event

e.g. If we arrive late, the teacher won't be pleased.

Si nous arrivons en ******, le prof ne…