Even if vs. Even though

Even if and Even though seem to be the same but they are in fact different in meaning and usage.
As a matter of fact ,this two conjuctions are if and though.Addition of even before them doesn't change the meaning of though but changes the meaning of if.

Even if
As is is used to say that something will not have any effect on a situation,It could mean whether or not.As if introduces a conditional clause.

- He's going to buy the farm even if they raise the price.
- Even you'll take a taxi,you 'll miss your train.
- Even ih I had talent to play tennis, I couldn't stand the pressure.

Even though
Even though means although but is a stronger form of the word and makes the other main statement surprising and it introduces a contrast clause.

- Even though I'm supposed to be working by myself,there are other people who I can interact with.
- Even though he left school at 16,he still managed to become prime minister.
- I used to love listening to her,even though I could only understand only half of what she said.

To understand better the difference between even if and even though note the following comparison:

Example 1

- His mother has promised him a bike him even if he doesn't promises to study harder.
- His mother has promised him a bike him even though he will not promise to study harder.

The first sentence means that his mother will buy him a bike whether or not he promises to study harder.
The second sentence,whereas ,indicates that he will not promise to study harder,he still receives the bike.

Example 2

- She wears a fur coat even if it is a hot day.
- She wears a fur coat even though it is/will /may be a hot day.

The first example implies that if it happens to be hot, she wears the fur coat.
The second one signifies that she already knows it is hot, she still wears the fur coat.

Even if usually means that an event has not happened or has not realized yet.
Even though could mean that in spite of the fact that the event has happened or will happen.

In the sentence with even if speaker doesn't know whether the event will happen or not, he or she,however, will do the action.
In the sentence with even though speaker knows the event has happened or will happen, he or she still does the action.

Example 3

- I will ask my friend the math question even if he doesn't know the answer.
- I will ask my friend the math question even though he will not/may not know the answer .

In the first sentence, speaker says I will ask the question whether or not my friend knows the answer. The second one , whereas , speaker means I know that my teacher doesn't know the answer, but I will ask the question.

Notice that even if acts like the if conditional structures and usually doesn't take the modals but the even though clauses can come with the modals as shown in the instances.

For additional information about even though click here.

As if vs. As though

As if and as though are two conjunctions that introduce subjunctive and indicative sentences.
They can be interchanged in many occasions. So they mean the same:
If something happens as if/as though something else were true, it happens in a way that it reminds you of it.

They have three definitions:
1- In a way that suggests something is true.

- Brian shook his head as if to say:"don't trust her"
- You look as if you 're having a good time.
- He looked at me as though defying me to argue.

2- In a way that indicates something is unlikely and should not be considered.

- He looked at me as if I was mad.
- He ran as though ghosts were chasing him.
- I got treated as if I was brainless.

3- They mean that when they come with such verbs as:"seem,appear,look,feel,sound"

- It seemed as if the day would never end.
- She sounds as if she's really sick.
- I felt as though all my strength had gone.

Learners' common errors

1- Many people regard it as incorrect to use was instead of were in this type of sentences.
Were or was(more common) both can be used in conversation but in formal style were is preferred.

- She talked if she was rich.

2- One of the most frequently asked questions is the tense of sentences and its usage in this instruction.
We can use a past tense with a present meaning after as if/as though indicating that a comparison is unreal.

- He talks as if he's our boss.
- He talks as if he was our boss.

The first sentence shows that he may be our boss. The second sentence,whereas indicates he is not our boss.

As if / As though +present Tense

A- He acts as if he doesn't know me.(At the present time, He really doesn't know me.)

As if / As though +Past Tense

B- He acts as if he didn't know me.( At the present time, He pretends that he doesn't know me or I'm not not sure whether he knows me.)

As if / As though +Past Perfect

Although There are conflicting arguments about the form of as if and some people regard it as incorrect to use it and some other believe there is no difference between this and the previous construction -B, some think that it is used for unreal situations and some maintain that it is used in both real and imaginary occasions,however we consider the likeliest usage which is the following definition for this use of as if :
- If we talk about a hypothetical past situation, the past perfect tense is used.
C- He acted as if he hadn't know me.(He pretends that he doesn't know me, but I know you do)
- He seems as if he hadn't slept for days.(He seems not to have slept for days, but I know he has.).
Note that this structure is like the former two ones is present tense.

Past Tense + as if /as though + Past Tense

D- He acted as if he didn't know me.( In the past, he didn't really know me)

Past Tense + as if /as though + Past Perfect

E- He acted as if he hadn't known me.( In the past , he pretended that he hadn't known me or may be he hadn't known me.).

3- The use of as if or as though sometimes is a matter of collocation.In many cases both can be interchangeably used but sometimes for the reason of collocation, one is preferred to the other one,for example in the following sentence as if is more common than as though,although the latter is not grammatically incorrect.

- He acts as if he doesn't know me.
- You turn on the television and look through the list of new movies, as if you have a video store in your home.Y

As if/As though can:

4- be associated with adverbs or adjectives:

- After asking her age, she stood a moment, as if embarrassed.
- She moved her leg,as though in pain.
- He fell over backwards and lay,as if struck by lightning.
- Garin shot him a dark glance, as though in warning.
- Jill crossed her legs and rested her chin on one fist,as if lost in deep thought.
- The crowd suddenly silenced, as if by magic.

5- come with ing and infinitive forms.

- He paused and cocked his head,as if listening.
- He ran off to the house, as though escaping.
- She pursed her lips together,as though fearing to betray her news.
- Albert opened his mouth as if to protest.
- He step forward as though to kiss his mother.

6- can be associated with a preposition:

- She was trembling as if with fear.
- He leaned against his father as though for support.

7- may be placed at the beginning of a sentence.

- As if to remind him,the church clock struck eleven.
- As if we don't belong to ourselves?

As vs. Though

As and Though are two conjunctions that can be used after adjectives or adverbs meaning Although:

- Unlikely as /though It might seem ,I'm tired too.
- Hard as/though she worked, she failed in his exam.
- Tired as/though I was ,I took her to the station.

They can indicate an emphatic contrast.
As comes with much ,but not though.In this use,it is used in sentence initial position and doesn't come with adjective or adverb.

- Much as /though he seemed to be hungry , he didn't eat so much.
- We went on a one week trip last week,as much/though we were busy.

As in this structure can be used to mean because:

- The horrible as the movie was, the people under 16 were not allowed to watch it.
- The rich as he was, he could afford the luxury cruise ship.

Although and Though can be used alone with adverbs and immediately after them.

- The marriage ,although/though brief,was a happy one.
- The doctor ,although/though experienced, could not diagnosis her cancer.
- Although/Though shy, she took part in many parties.

Though can be used in the middle of a sentence between two clauses to mean although.

- It might be worth your while to go to the court,though,and you 'll need expert advice.
- I enjoyed the movie,though I thought it was too long.

Though can also be used at the end of the sentence as an adverb meaning however,nevertheless.

- It's a hard work.I enjoy it though.
- He speaks many languages. He does know Spanish,though.

Although ,Though,Even though, As though

Although ,though,even though all mean the same thing with subtle differences ,not in meaning ,though.

Though is more common in informal style.

Even though is a stronger form of although.

- Although/Though/Even though he played brilliantly, he still lost her match.

Though like however,nevertheless and all the same can appear at the end of a sentence as an adverb,but not although or even though.In this use ,it means however.

- He lost the match,he played brilliantly, though.
- I enjoyed the movie,though, I thought It was too long.
- The strongest argument,though is economic and not political.

Though can be used after an adjective,either.

- Tired Though he was,he stayed up until midnight.
- Hard though I studied,I failed in my test.
- tempting though the snacks were,I refused to eat them.

But as though means differently.It means as if.

- She treats him as though he were her son.

For more information about "though" click here.