411 on Conditional Sentences

Site: http://www.englisch-hilfen.de/en/grammar/if.htm

Conditional sentences

The conditional sentences are sometimes confusing for learners of English.

Watch out:

1) Which type of the conditional sentences is used?

2) Where is the if-clause (e.g. at the beginning or at the end of the conditional sentence)?

There are three types of the if-clauses.

type	condition
I	condition possible to fulfill
II	condition in theory possible to fulfill
III	condition not possible to fulfill (too late)

Form

type	if clause	main clause
I	Simple Present	will-future (or Modal + infinitive)
II	Simple Past	would + infinitive *
III	Past Perfect	would + have + past participle *

Examples (if-clause at the beginning)

type	if clause	main clause
I	If I study,	I will pass the exam.
II	If I studied,	I would pass the exam.
III	If I had studied,	I would have passed the exam.

Examples (if-clause at the end)

type	main clause	if-clause
I	I will pass the exam	if I study.
II	I would pass the exam	if I studied.
III	I would have passed the exam	if I had studied.

Examples (affirmative and negative sentences)

type		Examples
		long forms	short/contracted forms
I	+	If I study, I will pass the exam.	If I study, I'll pass the exam.
	-	If I study, I will not fail the exam. If I do not study, I will fail the exam.	If I study, I won't fail the exam. If I don't study, I'll fail the exam.
II	+	If I studied, I would pass the exam.	If I studied, I'd pass the exam.
	-	If I studied, I would not fail the exam. If I did not study, I would fail the exam.	If I studied, I wouldn't fail the exam. If I didn't study, I'd fail the exam.
III	+	If I had studied, I would have passedthe exam.	If I'd studied, I'd have passed the exam.
	-	If I had studied, I would not have failedthe exam. If I had not studied, I would have failedthe exam.	If I'd studied, I wouldn't have failed the exam. If I hadn't studied, I'd have failed the exam.

* We can substitute could or might for would (should, may or must are sometimes possible, too).

I would pass the exam.

I could pass the exam.

I might pass the exam.

I may pass the exam.

I should pass the exam.

I must pass the exam.

Exercise: http://www.ego4u.com/en/cram-up/grammar/conditional-sentences/exercises?06

Exercises on Conditional Sentences (Mix)

Exercise on Conditional Sentences Type I, II and III

Complete the Conditional Sentences (Type I, II or III) by putting the verbs into the correct form.

1. If they (have)  time at the weekend, they will come to see us.
2. If we sneak out quietly, nobody (notice) .
3. If we (know)  about your problem, we would have helped you.
4. If I (be)  you, I would not buy that dress.
5. We (arrive)  earlier if we had not missed the bus.
6. If I didn't have a mobile phone, my life (not / be)  complete.
7. Okay, I (get)  the popcorn if you buy the drinks.
8. If I (tell)  you a secret, you would be sure to leak it.
9. She (go)  out with you if you had only asked her.
10. I would not have read your diary if you (not hide)  it in such an obvious place.