Conditional Sentences

 "If you can't explain it simply, you don't understand it well enough." - Albert Einstein

 

Conditional sentences, or "If-Clauses", are statements about possible or hypothetical actions and their consequences. 

If I understand this example, I will get better grades in English.

  condition                              consequence

There are four different types of conditional clauses. All of them express a different degree of probability that the respective consequence happens. 

 

It doesn't matter in which sequence the clauses are placed, just remember to add the comma if the if-clause is placed first!

 

All conditionals can express continuous actions as well, simply use the progressive form of the correct tense.

Overview

 

Zero Conditional First Conditional Second Conditional Third Conditional
When I do my homework, I get good grades. If I do my homework, I will get good grades. If I did my homework, I would get good grades. If I had done my homework, I would have gotten good grades.
Simple Present

Simple Present

+ Simple Future

Simple Past

+ auxiliary modal verb + infinitive

Past Perfect

+ auxiliary modal verb + have + past participle

guaranteed

likely not likely, unrealistic

likely, but since it happened in the past

→ impossible

Zero Conditional

The Zero Conditional is used to express general truths, for example, scientific occurrences. One action or situation always causes another. Both clauses are written in the Simple Present.

The if-clause doesn't need to start with an "if" in this case. "When" and "if" can be used interchangeably.

It is also used to give instructions.

Examples

  • If/When you heat ice, it melts.
  • If/When it rains, the ground gets wet.
  • Water becomes solid if/when you freeze it.
  • Plants don't die if/when you take care of them correctly.
  • If you don't know the answer, ask me.

First Conditional

The First Conditional is used to express situations, that are very likely but not guaranteed to happen in the future. One action will most likely cause a specific situation. Simple Present is used in the if-clause, while the main clause is written in Simple Future ("will-future").

 

Examples

  • If you get enough sleep, you will feel more energized.
  • If we wake up early, we will catch our train.
  • Louis will buy the new action figure if it is available.
  • He will save his money if he can't get the figure he wanted.
  • I won't travel to Hongkong if the political situation doesn't improve soon.

Second Conditional

The Second Conditional is used in situations that are completely unrealistic or not very likely. The conditional part is written in Simple Past, while the main clause consists of an auxiliary modal verb and an infinitive.

Auxiliary modal verbs are e.g. would, could, might or should.

 

 

Examples

  • If I won the lottery, I would buy a castle.
  • If Sarah didn't have to work today, she would come to visit.
  • I could stay longer and help out if I felt like it.
  • Lisa couldn't attend the concert even if she didn't have school.
  • If I were you, I would change my job.

Third Conditional

The Third Conditional is used to describe situations where the  circumstances would have been different if something had happened in the past. A situation was likely/possible in the past but did not happen.

To form this structure, you need to use the Past Perfect in the conditional sentence and an auxiliary modal verb plus have and past participle.

Examples

  • If I had studied for the test, I would have gotten an even better grade.
  • Nico could have been on time if he hadn't missed his train.
  • If you hadn't done your homework yesterday, you couldn't have gone to the movies earlier today.
  • Marie should have cleaned her room if she had wanted her friends to come over.

Special Cases

 

  

As with all grammar topics, the rules are never complete without some exceptions.

Let's take a look!

Mixed Form

In case a certain action could've happened in the past, which would change the current circumstances, a mixed form between the third and second conditional is used. Usually, those sentences include a signal word like now. It's also commonly used with stative verbs (refer to Tenses).

Examples

  • If I had studied, I would know who was the first president of the USA.
  • Max could be playing video games now if he had done his homework earlier.
  • If Vaughn had won the lottery, she would be rich.
  • Abby would be in Germany now if she hadn't had to cancel her flight two days earlier.

Will/Would/Could in If-Clause

The Simple Future ("will") is generally not used in the if-clause. However, if the action in the if-clause takes place after the action in the main clause, it is possible to use this construction.

 

  • If an aspirin will ease my headache, I will take some later.

 

The other exception is if the verb is not used as an auxiliary verb but as a modal verb, to express willingness politely.

 

  • I will warm some milk for a hot chocolate if you will excuse me.

 

This is also possible with "could" and "would". Structures like this are often used in the context of inquiries.

 

  • We would be grateful if you would be so kind to send us your latest catalog.