Learning goals
Recognize meaning, choose the correct verb forms, and produce affirmative, negative, and interrogative conditionals.
An interactive Semong-style lesson on first, second, and third conditionals
Recognize meaning, choose the correct verb forms, and produce affirmative, negative, and interrogative conditionals.
Explanation 15 min · Reading 15 min · Controlled practice 30 min · Production 15 min.
I can explain why a situation is possible, imaginary, or impossible because it is in the past.
Your enormous sandwich disappears from a locked refrigerator. What will you check first? Who would be your most ridiculous suspect? What could you have done to prevent the crime?
Conditional sentences connect a condition with its result. Choosing the correct conditional is not only a grammar decision; it shows how the speaker sees the situation. Is it a genuine future possibility, an imaginary or unlikely idea, or an impossible past that can no longer be changed?
If the chef finds the sandwich thief, he will call the manager.
If the lights do not come back on, we will use candles.
Will you scream if the refrigerator opens by itself?
The condition is realistic. The speaker believes it can happen.
If the sandwich could talk, it would identify the thief.
If I were not so hungry, I would not enter that kitchen.
What would you do if a pickle followed you?
The past form creates distance from reality; it does not necessarily describe past time.
If the guard had locked the pantry, the thief would not have escaped.
If we had not followed the crumbs, we would have missed the clue.
Would you have believed me if you had seen it?
Both actions are past and finished. We imagine a different version of history.
Compare the same basic idea. If Marco studies tonight, he will pass presents studying as a real possibility. If Marco studied more, he would pass suggests that he probably does not study enough. If Marco had studied, he would have passed tells us that the exam is over and he did not pass.
The condition and result can change places without changing the central meaning:
Use a comma when the if-clause comes first. A comma is not normally needed when the result comes first.
Either clause can be negative: If Nora doesn’t hurry, she won’t catch the bus. For questions, put the auxiliary before the subject in the result clause: What will Nora do if she misses it? Where would she go if she had more time? Would she have arrived earlier if she had taken a taxi?
Unless means if not. Use it with a positive verb when the intended meaning is negative: Unless you whisper means if you do not whisper. Avoid a double negative such as Unless you don’t whisper when you mean “if you do not whisper.” Other useful connectors include as long as, provided that, and even if.
The result does not always need will or would. Use might for possibility and could for ability or another possible result: If we search the pantry, we might find a clue. If I were taller, I could reach the top shelf. If the guard had looked up, he might have seen the thief.
Decision test: Can it realistically happen later? Use the first. Is it imaginary or unlikely now/later? Use the second. Is it an alternative to a finished past event? Use the third.
At exactly 11:47 p.m., Detective Priya Pepper received the most unusual emergency call of her career. The Grand Crumb Hotel’s famous Midnight Monster sandwich had vanished from a locked refrigerator. It was taller than a birthday cake, contained seven cheeses, and was supposed to be presented to a food critic at midnight. “If we do not find it in thirteen minutes,” Chef Bruno cried, “the critic will give us a terrible review—and I may have to cook vegetables!”
Priya entered the dark kitchen with her assistant, Ollie. A single pickle lay on the floor like a tiny green warning. The refrigerator door creaked open by itself. Ollie grabbed a frying pan for protection, although it was the smallest pan in the kitchen. “If a ghost appears,” he whispered, “I will hit it with this.” Priya looked at the pan. “If I were a ghost, I would be deeply embarrassed for you.”
A trail of mustard led through the pantry and stopped beside an enormous sack of flour. Something inside the sack sneezed. Priya raised a rolling pin while Ollie hid behind a loaf of bread that was not remotely large enough to hide him. If Ollie had chosen a bigger loaf, his knees would not have been visible. The sack moved again. Then a white, powdery figure leaped out and shouted, “Do not eat me!”
It was Bernard, the night manager. He had fallen into the flour while investigating a noise. His black suit was now completely white, except for two mustard handprints on his back. “If someone had warned me about the loose shelf,” he complained, “I would have worn my less expensive trousers.” Priya noticed that Bernard was holding half a tomato. He claimed it had attacked him.
Suddenly, the hotel lights went out. In the darkness, they heard slow footsteps, heavy breathing, and a wet chewing sound. Ollie’s frying pan trembled. “Unless everyone stays calm, we will frighten the thief away,” Priya said. A voice behind them replied, “Too late.” When the emergency lights blinked on, the tomato was gone from Bernard’s hand—and the pickle had moved three meters closer.
The three investigators followed the chewing sounds into the ballroom. A shadow crossed the curtains. Priya pulled them aside and discovered Marmalade, the hotel cat, wearing a paper chef’s hat. There was cheese on his whiskers, but the giant sandwich was nowhere nearby. “If Marmalade were the thief,” Priya reasoned, “he would not have such a small stomach—or such an innocent face.” Marmalade immediately stole Ollie’s shoelace, weakening the argument about innocence.
At 11:57, Priya found the final clue: four tiny wheels marked the carpet beneath the buffet table. The sandwich had not walked away; it had rolled away. Someone had built it on a serving trolley and forgotten to lock the wheels. The trolley had travelled down a sloping corridor, through the laundry room, and into the service elevator. If Chef Bruno had locked the wheels, the sandwich would have stayed in the kitchen.
The elevator bell rang. Everyone froze. The doors opened slowly, revealing the complete Midnight Monster sandwich—and a very surprised food critic trapped behind it. He had been trying to push it back upstairs for ten minutes. “If you add wheels to dinner,” he said, “you will need traffic signs.” He gave the hotel five stars for flavor, three stars for safety, and one extra star because Marmalade looked excellent in a chef’s hat.
PRIYA: Chef Bruno, what will happen if we don’t find the sandwich?
BRUNO: The critic will destroy us. Worse, my mother will say, “I told you to make soup.”
OLLIE: If I were the thief, I would leave the country immediately.
PRIYA: If you were the thief, you would leave your name and address at the scene.
OLLIE: That happened only once.
BERNARD: If the pantry light had worked, I wouldn’t have fallen into the flour.
BRUNO: It would have worked if you had paid the electricity bill.
BERNARD: I paid it! I simply paid the hotel across the street by mistake.
PRIYA: Everyone will remain a suspect unless we find solid evidence.
OLLIE: What will we do if the thief is armed?
BRUNO: Armed with what?
OLLIE: Mayonnaise. It gets everywhere.
PRIYA: If I had known you were afraid of mayonnaise, I would have brought a different assistant.
OLLIE: If you replaced me, you would miss my excellent instincts.
PRIYA: I might miss your jokes. My aim is not perfect.
BERNARD: Listen! If we keep talking, we will lose that chewing sound.
BRUNO: If someone were eating my sandwich, I would hear crying. Seven cheeses are a serious commitment.
OLLIE: I found the criminal! It’s the cat!
PRIYA: Marmalade couldn’t have moved the trolley unless someone had trained him.
BERNARD: If I had trained a cat, it would do my paperwork, not steal sandwiches.
PRIYA: Look at these wheel marks. If we follow them, they will lead us to the sandwich.
OLLIE: And if they lead to a monster?
PRIYA: You can protect us with your extremely intimidating frying pan.
CRITIC: Could someone move this sandwich? If I stay behind it much longer, I will become dessert.
Answer from the story. Some questions check meaning as well as grammar.
Choose First, Second, or Third for each sentence.
Choose the correct verb form to complete each sentence.
Choose the ending that creates a logical and grammatically correct sentence.
Click a phrase from the bank to place it in the next empty blank. Click a filled blank to remove it. Each phrase is used once.
Each sentence contains one conditional error. Choose the best correction.
If you have free time this weekend, what will you do? Write three first conditional sentences, including one negative sentence.
If I have free time, I will visit my cousin. If the weather is bad, we won’t go hiking. What will we do if it rains?
If you could change three things about your town or school, what would you change? Include one question.
If I could change my town, I would add more parks. I wouldn’t allow cars downtown if public transport were better. What would you change if you were the mayor?
Imagine you missed an important event. Explain three things that could have changed the result.
If I had remembered the time, I would have left earlier. I wouldn’t have missed the event if I had checked my calendar. Would I have arrived on time if I had taken a taxi?
Continue Priya’s investigation with at least one first, one second, and one third conditional. Underline the verb forms when you share your answer.
First: a possible next event. Second: an investigator’s imaginary choice. Third: a different past action and result.
| Type | Time and meaning | If-clause | Result clause |
|---|---|---|---|
| First | Possible future | present simple | will + base |
| Second | Unreal present/future | past simple | would + base |
| Third | Unreal past | past perfect | would have + past participle |
Rewrite one sentence from each type as a negative, then turn another sentence from each type into a question. Replace will or would with might or could where the meaning is logical.