Subjunctive Mood

Moods is the way to express the attitude of the speaker to what is being said. Subjunctive means subordinate or dependent. A subjunctive mood expresses something that is not fact like possibilities, doubts, wishes, desires, suggestions, or conditions.We use subjunctive when we
• want something to happen,
• imagine something happening, or
• anticipate that something will happen.

[1] EXPRESSING DESIRE/SUGGESTION

There are two common forms of subjunctive used to express desire or suggestion.

VERB + THAT + SUBJECT + VERB

The common verbs used in this structure are: ask, command, demand, insist, propose, recommend, require, suggest, urge, warn, etc. For examples,

• The teacher suggested that she study harder.
• The doctor recommended that he not eat salty food.
• My mom insists that I get up early.
• We urged that he deliver the raw materials on time.

Note: We also use "should + infinitive" instead of subjunctive.

ADJECTIVE + THAT + SUBJECT + VERB

These adjectives are: critical, important, essential, necessary, vital, etc. For examples,

• It is important that you study hard.
• It is vital that students not cheat during exams.
• It is essential that she be on time.
• It is necessary that he wear helmet.

[2] EXPRESSING POSSIBILITIES

Subjunctive mood is used to make prediction/assumption; for examples,

• It may rain tomorrow.
• We will go on holiday.
• All of these problems could happen.
• It's going to be a tough job.

Subjunctive mood is used to express conditions; for examples,

• If you heat the water to 100 degree, it boils.
• If you don't breath, you die.
• If you park here, the police will fine you.
• If I have money, I will lend you some.

[3] EXPRESSING A CONTRARY TO THE FACT

Subjunctive mood is used to express the contrary to the present with the following structures.

- If + past simple
- Wish /if only+ past simple
- As if / as though + past simple

For examples,
• If I were rich, I would buy that school.
• I wish I were able to finish my work on time.
• He speaks as if he were my boss.
• I doubt if you would go with us.

Subjunctive mood is used to express the contrary past with the following structures.

- If + past perfect simple
- Wish/if only + past perfect simple
- As if/as though + past perfect simple

• If I had studied hard, I would not have failed my test.
• Had he been more careful, the accident would not have happened.
• I wish I had not spoken such stupid words.
• He behaved as if he had not done anything wrong.

Only if

Only if is used expresses the meaning of "in case" or "only in the case". You need to differentiate between "only if" and "if only". For examples,

• We will cancel the picnic only if it rains. [if there is storm, sunny, windy…., we will have a picnic. So, the cause that can make us to cancel the plan is only rain.]
• Call me only if your cold gets worse. [Only when your cold get worse, you can call me. ] 
• Only if everybody agreed would I accept this position. [I would accept this position only if everybody agreed.] 

As if / As though

'As if' or 'As though' is used to show how something is like.

1. As if / as though + present simple: 

It is used to express something or someone seems like. For examples,

• It looks as if it might rain. [The sky turns dark, and it will possibly rain.] 
• He works on the computer as if/though he's skillful. [He can do things, and he probably can fix it.]

2. As if / as though + past simple:

It is used to express something is presently unreal. For examples,

• She tells me as if/though she knew the story. [She obviously doesn't know the story.]
• He walks as if/though he were an old man. [But in fact he's a young man.]

Compare the following two sentences:

• He looks as if/though he's sick. [He is sick.]
• He talks as if/though he were sick. [He's actually well.]

3. As if / as though + past perfect simple:

It is used to express something was unreal in the past. For examples,

• He looked as if/though he had done something. [He didn’t do anything wrong.]
• They responded as if/though the problems were not serious. [The problems were serious.]

Wish / If only

'Wish' or 'if only' is used to express a complaint, a wish, or a regret.

[1] Wish / if only + would + infinitive

It is used to show complaints about a situation; the speaker also expects a change in the future. For examples,
• I wish you wouldn't make the same mistake. [You usually make the same mistake.]
• I wish you wouldn’t drive so fast. [You drive too fast.]
• I wish my neighbors would not make so much noise.
• We wish our boss would give a pay rise.
[2] Wish / if only + past simple

It is used to show a state that a speaker is not satisfied with something presently and she wants to change it. For examples,

• I wish the room were colder. [The room is hot.]
• If only I was not fat, I would buy these clothes. [You are fat. The clothes do not fit you.]
• My computer broke down. If only I knew how to fix it!
• I hate traveling and traffic jam. If only I lived nearer the office.


[3] Wish / if only + past perfect simple

It is used to express regret about past actions (the speaker wants to change the past). For examples,

• I wish I hadn't drink so much. [I drank a lot then.]
• If only I had studied hard, I would have passed the exams. [I didn't study hard, and I failed in the exams.]
• We wish we had attended the meeting.
• We got wet. I wish we had brought the umbrella.

NOTE: Wish + to do something = means "would like/ want"; for example, 

• I wish to finish the assignment today. = I would like /want to finish the assignment today.

Third Conditional

FORM

If + past perfect simple, sub + would + have + verb 3 (past participle)

Note:
- If + past perfect simple = i.e. unreal past situation/condition
- subject + would + have + verb 3 = i.e. impossible result
- You can use some modals like could instead of would.


USAGE

We use third conditional to talk about unreal (not true) past situation(s) and its impossible result(s). For examples,

• If I had studied hard, I would have passed the exam. [= I didn't study, and I failed the exam. ]
• If she had come to the party, she would have met Sophal. [= She didn't come and didn’t meet John. ]
• We would have gone out last night if we hadn’t been so tired.
• If I had known you didn’t have a car, I would have given you a lift.
• If she had paid attention in class yesterday, she would have heard that we have a quiz today.

Second Conditional

FORM

If + past simple, sub + would + verb (present)

Note:
- If + past simple = i.e. unreal present situation/condition
- subject + would + verb 1 = i.e. probable result
- You can use some modals like could instead of would.


USAGE

We use second conditional to talk about unreal (not true) present situation(s) and its probable result(s). For examples,

• If I had enough money, I would buy a big house. [ = Now I don’t have money. ]
• If I were a writer, I would write about your love story. [= I am not a writer now. ]
• If he studied harder, he would pass the exam. [= He didn't study hard.]
• If he stopped smoking, his cough would get better. [= He doesn't stop smoking.]
• If I had some free time, I would visit you. [= I don't have much free time.]

First Conditional

FORM

If + present simple, future simple

Note:
- if + present simple = i.e. real things (situation or condition)
- present simple = i.e.likely result
- You can use some modals like can, may, might, and should instead of will.


USAGE

We use first conditional to talk about future possibility (condition) and its probable result. For examples,

• If you work hard, you will pass the exam.
• If I meet him, I will tell him.
• If you don’t listen carefully, you won’t be able to do your assignment.
• If you travel by plane, you will spend more money.
• If you buy her a present, she will be happy.

Zero Conditional

FORM

If + present simple, present simple

Note:
- if + present simple = i.e. real things (situation or condition)
- present simple = i.e. real result

USAGE

Zero conditional is used to talk about facts / something that will definitely happen when the condition is true (or happens); for examples, 

• If you press that button, the lights turns off.
• It turns gray if we mix black and white.
• If water gets 100 degree Celsius, it boils.
• If you touch a fire, you get burned.
• People die if they don't eat.