Conditional Sentence

A zero-conditional sentence expresses a general fact (i.e., a situation where one thing always causes another).

• If you rest , you rust. (Actress Helen Hayes)
• If you think you can , you can. And if you think you can't , you are right. (Business magnate Henry Ford)
• You do ill if you praise , but you do worse if you censure , what you do not understand. (Polymath Leonardo da Vinci)

• If I make money , I'm happy. When I lose money , I'm happy. (Gambling magnate Lui Che Woo) (With a zero-conditional sentence, the message is expressed as a fact. That doesn't mean it's true of course.)

First Conditional Sentences

A first-conditional sentence states the result of a hypothetical, but possible, future event (e.g., If you rest) occurring.

• If one swain [young lover] scorns you , you will soon find another. (Roman poet Virgil)
• If I like a food, even if it's bad for me , I will eat it. (Reality TV star Kim Kardashian)

Second Conditional Sentences

• If I won the lottery , I would still love you. I'd miss you, but I'd still love you. (Comedian Frank Carson)
• If I saw a heat wave , I would wave back. (Comedian Steven Wright)
• If I had any humility , I would be perfect. (Media mogul Ted Turner)
• If you set out to be liked , you would compromise on everything and achieve nothing. (Margaret Thatcher)

Nowadays, it's safe to say that the simple past tense is used in the if-clause, but in fact it's the past subjunctive, which is identical to the simple past tense apart from when I and he/she/it are used with the verb to be (e.g., If I were millionaire, If she were to try). (There's an entry on the subjunctive mood.)

• If I were a rich man , all day long I'd biddy-biddy-bum. (Extract from "Fiddler on the Roof") (I'd is short for I would. To biddy-biddy-bum must be a verb.)
• Life would be tragic if it weren't funny . (Theoretical physicist Stephen Hawking)

• If I was a man , I don't know whether I'd settle down long before I was 50. (Journalist Mariella Frostrup)

Third Conditional Sentences

Third-conditional sentences express how the situation would be different if the past had been different.

• If my lawyer and I had communicated properly in January 1958 , this whole history would have been entirely different. (Inventor of the laser Gordon Gould, who fought unsuccessfully to patent it)
• If I had learned education , I would not have had time to learn anything else. (Business magnate Cornelius Vanderbilt)
• If I had known how hard it would be to do something new in the payments industry , I would never have started PayPal. (Co-founder of PayPal Peter Thiel)

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More about Conditional Sentences

• I will swim unless the water is too cold .
• I will swim as long as the water is not too cold .
• I will swim provided that the water is not too cold .

• If we were smarter , we wouldn't have set off in this weather. (The if-clause is second-conditional structure. The main is third-conditional structure.)
• If you had checked the weather , we wouldn't be stranded now. (The if-clause is third-conditional structure. The main is second-conditional structure.)

Why Conditional Sentences Are Important

Fortunately, the vast majority of native English speakers can create conditional sentences of all 4 "flavours" and the mixed "flavours" without tripping themselves up. It's because native English speakers are naturally great at tenses. That said, there are some fairly common hiccups related to tense worth covering and also a point on using commas.

(Point 1) Using a comma with an if-clause.

• If I were white , I could capture the world. (African-American actress Dorothy Dandridge, 1922-65)
• If you steal from one author , it's plagiarism; if you steal from many , it's research. (Playwright Wilson Mizner)

• Dreams grow if you grow . (Author Zig Ziglar)
• There are consequences if you act militarily , and there are big consequences if you don't act . (US Diplomat Dennis Ross)

• There are economic risks if we leave. If we remain , there are economic risks. (Politician Michael Gove)

(Issue 2) Using the wrong tense in one of your clauses.

Tense errors can creep in. Below are the most common ones with each structure.

Zero-conditional Structure. To express something as a fact, writers should use the zero-conditional structure (if + simple present tense, simple present tense). However, writers sometimes use the first-conditional structure (if + simple present tense, simple future tense), which states the result of a possible future event occurring.

• If you sleep , you will dream.
• When dogs die , they will go to doggy heaven. (In both examples, the will should be deleted.)

• If you will get some sleep , you will feel better.
• You can have everything in life you want if you will just help other people get what they want . (Author Zig Ziglar) (In both examples, the will should probably be deleted.)

Second-conditional Structure. With the second-conditional structure, writers sometimes use the simple present tense (instead of the simple past tense) in the if-clause.

• If you become an insomniac , you would understand. (If you became an insomniac would be correct.)

• If you became an insomniac , you will understand. (You would understand would be correct.)

• If you would have slept last night , you would have beaten your record. (If you had slept last night would be correct.)

Key Points

• When the if-clause is before the main clause, use a comma.
• Do not use a comma when the if-clause is after the main clause.

This page was written by Craig Shrives.