Thursday, December 27, 2007

Conditional sentences

This is just a basic introduction to conditionals. We'll cover it in more detail later in Grammar Basics.

Type 1:
  • present tense: if-clause verb
  • main clause verb: future simple
  • Meaning: Probable – present or future

If it rains, we will stay home.
If it gets dark, we’ll turn on the lights.

  • (if + present) + may/might
  • Meaning: Possibility
  • Examples:
    • If it snows too much, we might have to stay home from school.
    • If he eats too much, he may get a stomachache.

  • (if + present) + may/can
  • Meaning: Permission; possibility
  • Examples:
    • If you finish your homework, you may go outside and play.
    • If he cleans his room, he can take a break.

  • (if + present) + must, should, etc.
  • Meaning: Request or advice
  • Examples:
    • If you catch a cold, you should stay in bed and drink plenty of fluids.
    • If it snows, you must shovel the sidewalk.

  • (if + present) + another present tense
  • Meaning: Automatic or habitual results
  • Examples:
    • If the power goes out, the emergency backup lights come on.
    • If he gets a haircut, he tips 20%.

  • if + present continuous
  • Meaning: Present action or future arrangement
  • Examples:
    • If I eat one more piece of candy, I’m going to feel sick.
    • If Father comes home early, we will go to the park.

Type 2:
  • if-clause verb: past tense
  • main clause verb: conditional tense (would)
  • Meaning: Subjunctive (certain result)

If the baby fell, he would cry.
If I wrote a book, I would be famous.

  • (if + past) + might/could
  • Meaning: Possible result; ability or permission
  • Examples:
    • If it rained, the game might have been cancelled.
    • If the train was late, you could have taken the bus.

  • (if + past) + past tense
  • Meaning: Automatic or habitual reactions in the past
  • Examples:
    • If the baby cried, Mother would always pick him up.
    • If he got mail, Grandfather would sit on the porch and read it.

Type 3:
  • if-clause verb: past perfect tense
  • main clause verb: perfect conditional (would have)
  • Meaning: Unfulfilled

If I had known you were coming, I would have baked you a cake.
If I had gotten up early, I would have avoided the morning rush.

  • (if + past perfect) + might/could have
  • Meaning: Possibility; ability, permission
  • Examples:
    • If he had gotten good grades, he could have been accepted to his first-choice university.
    • If they had taken a trip to New York, they might have been on that plane that crashed.

  • (if + past perfect) + would have been –ing (continuous form of perfect conditional)
  • Examples:
    • If the police had caught him, he would have been wearing a prison uniform by now.
    • If he had been tired, he would have sleeping.

  • (if + past perfect continuous) + would have been –ed
  • Examples:
    • If it had been raining, the car would have been parked in the garage.
    • If he had been outside raking leaves all day, he would have been tired.

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