Conditional Sentences

4 Types of Conditional Sentences

Conditional sentences, like Result expressions, play a pivotal role in English communication by addressing both factual scenarios and hypothetical situations along with their potential consequences. These sentences establish that certain events or circumstances are true or occur only under specific conditions.

A comprehensive conditional sentence consists of a conditional clause, often introduced by “if,” and a consequent clause. Let’s delve deeper into the different types and structures of conditional sentences to gain a better understanding.

1. Zero Conditional Sentences:

Zero conditional sentences are used to express general truths or facts, where one event consistently leads to another. They emphasize a cause-and-effect relationship that is universally valid. For example:

  • If you expose metal to oxygen and moisture, it rusts.
  • When the temperature drops below freezing, water turns into ice.

In zero conditional sentences, both the conditional clause and the consequent clause employ the simple present tense. It’s crucial to avoid using the future tense, as zero conditionals deal with established facts rather than future possibilities.

Additionally, ‘if’ and ‘when’ can be used interchangeably in these sentences without altering the meaning, as the outcome remains constant whenever the condition is met.

2. First Conditional Sentences:

First conditional sentences are utilized to discuss situations where the outcome is probable but not guaranteed in the future. They often convey realistic possibilities based on present conditions. Examples include:

  • If it rains tomorrow, I will bring an umbrella.
  • If she studies hard, she will pass the exam.

In first conditional sentences, the conditional clause employs the simple present tense, while the consequent clause uses the simple future tense. This tense combination reflects the likelihood of the outcome if the condition is fulfilled.

3. Second Conditional Sentences:

Second conditional sentences are employed to address outcomes that are unlikely or improbable in the present or future. They typically involve hypothetical situations or wishes that are contrary to reality. For instance:

  • If I were president, I would implement significant reforms.
  • If I had a time machine, I would visit ancient civilizations.

In second conditional sentences, the conditional clause utilizes the simple past tense, while the consequent clause often incorporates a modal auxiliary verb (such as ‘would,’ ‘could,’ or ‘might’) to express the hypothetical outcome.

4. Third Conditional Sentences:

Third conditional sentences revolve around hypothetical scenarios that did not occur in the past and their potential consequences. They reflect on unrealized possibilities and regrets regarding past events. Examples include:

  • If they had listened to my advice, they wouldn’t be in this predicament.
  • If I had known about the traffic jam, I wouldn’t have missed my flight.

In third conditional sentences, the conditional clause features the past perfect tense, while the consequent clause combines a modal auxiliary verb (‘would have,’ ‘could have,’ ‘might have’) with the past participle form of the verb to denote the hypothetical outcome.

Special Cases in Conditional Sentences:

While conditional sentences generally follow straightforward rules, there are exceptions and special cases to consider:

  • The future tense is typically avoided in the conditional clause unless the action in the conditional clause is set to occur after the action in the main clause.
  • The phrase “were to” can be employed in conditional sentences to emphasize particularly dire or significant outcomes.

Punctuation in Conditional Sentences:

Punctuating conditional sentences is straightforward:

  • Use a comma after the conditional clause if it precedes the main clause.
  • No comma is necessary if the main clause comes first.

Other Expressions of Conditional Sentences


Conditional clauses can also start with the word “unless” which serves to denote a condition that, if not met, leads to a particular consequence. Essentially, “unless” carries a similar meaning to “if … not” or “except if.” The verb forms utilized within examples featuring “unless” closely mirror those used in sentences employing “if.” Specifically, the present simple tense is employed in the unless-clause, while verbs such as shall, should, will, would, can, could, may, or might are deployed in the main clause:

  • Unless I phone you, you can safely assume that the bus is running on time. (This implies that if I do not phone you, or except if I phone you, the train is likely on time.)
  • We’ll have to cancel the show unless we manage to sell more tickets at the last minute. (This indicates that if we do not sell more tickets, or except if we sell more tickets at the last minute, the show will be canceled.)

It’s crucial to bear in mind that “unless” is not employed for impossible conditions. For example:

  • If the government had not raised food prices, there would not have been so many protests.
  • (Incorrect:) Unless the government had raised food prices …

Furthermore, “unless” and “if” are never combined. For instance:

  • We’ll go to Lusaka tomorrow unless it Jane gets better.
  • (Incorrect:) We’ll go to Lusaka tomorrow unless if Jena gets better.

Should you” and “Had

In formal contexts, the construction “should” + subject + verb can be utilized in place of “if”:

  • Should you wish to see me tomorrow, please contact my secretary to arrange for the meeting.
  • (Alternatively:) If you should wish to see me tomorrow …

Similarly, “had” + subject + verb can replace “if” in third conditional sentences:

  • Had I known you were waiting outside, I would have invited you to come in.
  • (Alternatively:) If I had known you were waiting outside …

if + were to

Another formal structure is “if + were to,” employed when discussing improbable events:

  • If the Prime Minister were to resign, there would have to be a general election within 30 days.

Additionally, in more formal styles, “were” + subject-verb inversion + to-infinitive is used:

  • Were we to give up the fight now, it would signify the end of democracy in our country.

“As long as,” “so long as,” “providing,” etc.

Conditional clauses can commence with phrases like “as long as,” “so long as,” “only if,” “on condition that,” “providing (that),” and “provided (that)” to impose specific conditions or limits:

  • You can play in the living room as long as you refrain from making a mess.
  • So long as a tiger remains still, it remains invisible in the jungle.
  • The bank lent the company money on condition that they repay it within six months.
  • You can receive a senior citizen’s discount provided you possess a valid railcard.

“Or” And “Otherwise”

Furthermore, “or” and “otherwise” are often utilized with conditional meanings:

  • You’ve got to start studying, or you’ll fail all those exams.
  • We’d better send it express; otherwise, it’ll take days.


“Supposing” may be employed with a conditional meaning, inviting the listener to envision a situation:

  • Supposing I don’t arrive till after midnight, will the guest-house still be open?
  • Supposing you lost your passport, you’d have to go to the embassy, wouldn’t you?
  • Supposing he hadn’t recognized us – he might never have spoken to us.


By grasping these different types and structures of conditional sentences, along with their nuances and exceptions, writers can enhance the clarity and impact of their writing when discussing conditions and their potential outcomes. Additionally, employing tools like Grammarly can aid in refining spelling and grammar, thereby polishing the text for better comprehension and effectiveness.

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