This document discusses different types of if clauses and the tenses used in the main clauses. It provides examples of each type: Type 0 uses a present tense if clause and present tense main clause to express general truths. Type 1 uses a present tense if clause and future tense main clause to express probable future situations. Type 2 uses a past tense if clause and "would + infinitive" main clause to express unlikely past situations. Type 3 uses a past perfect tense if clause and "would have + past participle" main clause to express impossible past situations. The document concludes by summarizing the four types of if clauses.

3. If clause
Main clause

4. 1.If it _________ (rain) heavily, our house
_________ (leak).
2.If we ________ (put) ice in the sun,it
_________ (melt) quickly.
3.If we _____________(feel) well, we
________(see) a doctor.
4.If a dog ________ (see) stranger,it
________(bark).

5. v
Present
Future

6. 1.If you ____________ (work) hard,you_______
_______(fail).
2.If it ________(rain),I ___________(come)
and meet you in the car.
3.If it ___________ (rain) tomorrow,I _______
___________ (stay) at home.

7. n
Past tense / past subjunctive would+infinitive

8. 1.If I _________ (be) a bird, I _____________
(fly) everywhere.
2.If you _________ (tell) me the truth,I ______
_____________________ (give) you some
constructive advice.
3.If there _________ (be) a typhoon tomorrow,
I _______________ (be) very happy.

9. h
If I had had time last year,
I would have joined the Student Union.
Past Perfect
would + have + past participle

10. 1.If it ____________(rain) yesterday, I ___________
_____________(stay) at home.
2.If the principal __________________(allow) us to
supervise the tuck shop, food poisoning ____________
____________(occur) last Friday.
3.If the chairman _______________(ask) me to
help, I_______________(join) to fight for
better hygienic conditions.

11. Conclusion
If clause Main clause
Type 0
General Truth
Present
simple
Present
simple
Type 1
Probable situation
Present
simple
Future
Type 2
Unlikely to
happen
Past
simple
Would+
infinitive
tense
Type 3
Impossible
situation in past
Past
Perfect
Would+ have+
Past perfect