If + S + V1, S + V1

o Facts

Examples:If water boils, it changes into steam.If you sit in the sun, you get burned.

If + S + V1, S + will/going to + V1

o Event that are likely to happen in the future

Examples:If she wakes up now, she’ll be on time.If you watch this movie, you are going to love them.

If + S + V1, imperative+ V1

oA command or begging

Examples:If you finish watching TV, turn it off.If he comes, tell him the truth.

o It talks about things in the present.o It is possible but very unlikely, that the

condition will be fulfilled.

If + S + V2, would + V1

Examples:

If I were you, I would marry her.

If he knew the answer, he’d tell you.

o It talks about the past.

o It's used to describe a situation that didn't happen, and to imagine the result of this situation.

o IF Clause -If + Subject + Had + Past Participle.

o Main Clause -Subject + Modal + Have + Past Participle.

If + Subject + Had + Past Participle.

o If she had studied, she would have passed the exam (but, really we know she didn't study and so she didn't pass)

o If I hadn't eaten so much, I wouldn't have felt sick (but I did eat a lot, and so I did feel sick).

o If we had taken a taxi, we wouldn't have missed the plane

Subject + Modal + Have + Past Participle.

• She wouldn't have been tired if she had gone to bed earlier.

• She would have become a teacher if she had gone to university.

• He would have been on time for the interview if he had left the house at nine.

If + Past Simple , would have V3

It is impossible to happen in the present , but it affects the past

Example :•If she stayed here now, she would have seen her father.•If they were there, he wouldn’t have been alone.

If + Past perfect, would + V1.

It is impossible to happen in the past, but affects the present.

Example :•If you had listened to me, you wouldn’t be in trouble now.•If she had read her book, she wouldn’t fail the test.

Inversion of If Clause

Zero Conditional : when

Examples:

•If water boils, it changes into steam.When water boils, it changes into steam.

Inversion of If Clause

First Conditional : Should

Examples:

If she see David, she’ll pass on the message.

If she SHOULD see David, she’ll pass on the message.

Should she see David, she’ll pass on the message.

Inversion of If Clause

Second Conditional : Were

Examples:

•If I were you, I would tell him the truth.

Were I you, I would tell him the truth.

•If I went to Tokyo, I would go to Disneyland.

Were I to go to Tokyo, I would go to Disneyland.

Inversion of If Clause

Third Conditional : Had

Examples:

•If he had worked hard,… Had he worked hard,…

•If she had came here,.... Had she came here,….

• https://www.englishclub.com/grammar/verbs-conditional_4.htm

• http://www.learnenglish-online.com/grammar/thirdconditional.html

• Book: ตะลุยโจทย์ grammar 1,500 ขอ้• http://www.perfect-english-grammar.com/first-

conditional.html• https://www.englishclub.com/grammar/verbs-

conditional_5.htm