Conditional sentences type 0,1

 Conditional sentences type 0 is used for things that are genrally or always true

Form

If/when  subject+present simple,subject +present simple

Example

If the temperature of water rises to 100C.it turns into steam.

Conditional Sentences Type I refer to the future. An action in the future will only happen if a certain condition is fulfilled by that time. We don't know for sure whether the condition actually will be fulfilled or not, but the conditions seems rather realistic – so we think it is  likely to happen.

 

Form

if + Simple Present, will-Future

Example: If I find her address, I will send her an invitation.

The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Example: I will send her an invitation if I find her address.  

Note: Main clause and / or if clause might be negative.

Example: If I don’t see him this afternoon, I will phone him in the evening