No,
they are not interchangeable. If you want to use even though,
the meaning changes.
Even though means despite the fact that and is a more
emphatic version of though and although.
Even if means whether or not and has to do with the
conditions that may apply.
Compare
the following:
Even
if
I had two hours to spare for shopping, I wouldn't go out and buy
a suit.
Even
though
I had two hours to spare for shopping, I couldn't find the suit
I wanted.
The
first example describes an unreal situation where
we could substitute 'just supposing' for even if and say:
just supposing I had two hours to spare for shopping, I still
wouldn't go out and buy a suit.
The second example describes a real situation where
the shopper spent two hours looking for a particular kind of suit,
but couldn't find it. When we attach even tothough
in this way, we are in effect saying: you may find this surprising
but...!
Compare
the following pairs of sentences:
Even
though he lost his job as Arts Minister, he continued to serve
in the government.
Even if he loses his job as Arts Minister, I think he'll
continue to serve in the government.
Even
though the injury was serious, she decided to carry on playing.
It was an important match.
I
know she'll want to carry on playing, even if she gets
injured. It's an important match.
Even
though I've cleaned it and polished it, it still doesn't look
new.
Even if I clean and polish it, it still won't look new.
even
Note
that even cannot be used as a conjunction like even
if and even though when it stands alone.
We cannot say:
Even I've polished and cleaned it, it still doesn't look
new.
When even stands alone, it functions as an adverb
and means this is more than or less than expected. Again,
you are registering something that may be surprising when
you use it.
Study the following and note the position of even in these
sentences:
I
can't dive. I can't even swim!
She
speaks so many languages. German, Polish, Russian, Arabic, French,
Spanish. She even speaks Catalan!
Even
can also go at the beginning of a phrase when it refers to
words or expressions that we wish to emphasize, again because this
is surprising information for the listener:
He
works all through the year. Even at Christmas and New Year!
I
know his English isn't very good but even I can understand
him!
even
so
Even
so is a prepositional phrase that can be used in a similar
fashion to introduce a fact that is surprising in the context
of what has been said before. It
connects ideas between clauses or sentences:
I
know her English isn't very good, but even so I can understand
her.
The
evidence was only circumstantial. Even so, he was convicted
and spent ten years in prison for a crime that he perhaps did
not commit.
