Conditionals

Zero Conditional.

If + Subject +  Present Simple, Subject +  Simple Present 

If I go to a friend's house for dinner, I usually take a bottle of wine or some flowers

Subject +  Present Simple / if  + Subject +  Present Simple

I usually take a bottle of wine or some flowers if I go to a friend's house for dinner

USE

The zero conditional is used to talk about what you normally do in real-life situations also when we talk about things that are generally or always true.

Examples:

• When I have a day off from work, I often go to the beach.

• If the weather is nice, she walks to work.

• If we put water to heat, it boils

First Conditional.

If / unless + Subject +  Present Simple, Subject +  Will/won't + infinitive

If it rains, I will take my umbrella.

Subject +  Will/won't + infinitive if / unless + Subject +  Present Simple

I will take my umbrella if it rains.

      USE

The first conditional is used to talk about things which are possible in the present or the future — things which may happen:

UNLESS+ CONDITIONALS

Unless means the same as if...not. Like if, it is followed by a present tense, a past tense or a past perfect (never by 'would'). It is used instead of if + not in conditional sentences of all types:

Second Conditional.

If /unless + Subject +  Past Simple, Subject +  Would / wouldn't + infinitive

If I studied more, I would get better marks.

Subject +   Would / wouldn't + infinitive if unless + Subject +  Past Simple

I would get better marks if I studied more.

USE

The second conditional is used to talk about things which are unreal (not true or not possible) in the present or the future -- things which don't or won't happen: