There are 9 parts of speech or word classes in English language:
– nouns
– pronouns
– determiners
– verbs
– prepositions
– adjectives
– adverbs
– conjunctions
– interjections

We use conditional sentences to express:
– imagined situations
– results/consequences of situations

If I get a job in Singapore, I will be very happy.
If I get a job in Singapore = situation
I will be very happy = result/consequence

Usually, there are 2 clauses in a conditional sentence:
– if clause / conditional clause (for situations)
– main clause (for results/consequences)

If I get a job in Singapore, I will be very happy.
If I get a job in Singapore = if clause
I will be very happy = main clause

If a lot of people come, we will have to get extra chairs.
If a lot of people come = if clause
we will have to get extra chairs = main clause

There are 4 types of conditional sentences:
– Conditional Sentence Type 0 (Zero Conditional)
– Conditional Sentence Type 1 (First Conditional)
– Conditional Sentence Type 2 (Second Conditional)
– Conditional Sentence Type 3 (Third Conditional)

We use zero conditional to express:
– general truths (scientific facts)
Ice melts if you heat it.
If the sun goes down, it gets dark.

– something that always causes another thing to happen (can be subjective or objective)
If I drink too much coffee, I can’t sleep at night.
This fact is always true for the speaker (subjective).

If you don’t return the book on time, the library fines you.
This fact is always true for a lot of people (objective).

How to Form Zero Conditional

If clause:
If+ Present Simple Tense
If + Subject + base form / -s form

Main clause:
Present Simple Tense
Subject + base form / -s form

Ice melts if you heat it.
If clause: if you heat it (Subject + base form)
Main clause: ice melts (Subject + -s form)

We use first conditional to express:
– a situation in the future that is possible to happen
(real or possible future situations)

If it doesn’t rain tomorrow, we will go to the beach.
– The rain is possible to happen tomorrow.
– Going to the beach is also possible to happen tomorrow.

If I finish my work, I will call you.
– Finishing work is possible to happen.
– Calling you is possible to happen.

How to Form First Conditional

If clause
If+ Present Simple Tense
If + Subject + base form / -s form

Main clause
Future Simple Tense
Subject + will+ base form

If it doesn’t rain tomorrow, we will go to the beach.
If clause: if it doesn’t rain tomorrow (Subject + does not + base form)
Main clause: we will go to the beach (Subject + will+ base form)

We use second conditional to express:
– a condition in the present or future that is not possible to happen

If I inherited a billion dollars, I would travel around the world.
– From the point of view of this speaker, inheriting a billion dollars is not possible (maybe because he doesn’t have any family members with that much money)
– Because inheriting a billion dollars is not possible, traveling around the world is also not possible. This is an imagined situation.

If I knew where Tom lived, I would go and see him.
– From the point of view of this speaker, he does not where Tom lives.
– Because where Tom lives is unknown to the speaker, going and seeing him are also not possible to happen.

How to Form Second Conditional

If clause
If + Past Simple Tense
If + Subject + past simple

Main Clause
Subject +wouId + base form

If I knew where Tom lived, I would go and see him.
If clause: If I knew where Tom lived (Subject + past simple)
Main Clause: I would go and see him (Subject +wouId + base form)

For subjects I/he/she/it, we use “were” for the verb be (not “was”).

If I were you, I would take that job. (correct)
If I was you, I would take that job. (wrong)

We use third conditional to express:
– past action or event that might be different if a different action was done

If you had informed me, I would have waited for you.
What really happened:
– you did not inform me
– I did not wait for you

If I had studied harder, I would have passed the exam.
What really happened:
– I did not study harder
– I did not pass the exam

How to Form Third Conditional

If clause
If + Past Perfect Tense
If + Subject + had + past participle

Main clause
Subject + would + have + past participle

If I had studied harder, I would have passed the exam.
– If clause: If I had studied harder (Subject + had + past participle)
– Main clause: I would have passed the exam (Subject + would +
have + past participle)