'although' and 'eventhough' both have the same meaning yet we use 'even though' to emphasize something that is unexpected or to make a comparisson statement stronger. examine these: "Although she's rather annoying, I still love her." "Even though she's rather annoying, I still love her." the latter statement could possibly expresses the idea: "ADMITTEDLY, she's rather annoying...." while the former could go: "INSPITE OF THE FACT that she's rather annoying..." "though" has the same meaning with "although" yet sometimes, we use "though" at the end of the sentence (replaces 'but'). "a lot of food has been served. I didn't grab a bite though." :)

这四个词（词组）都有“虽然、即使、尽管”的意思。even if和even though带有较强的意味，语气比although和though强。though比although通俗，但不如although正式,都不能和but连用，但可以和yet, still或nevertheless连用。可以放在主句前面也可以放在主句后面。 1. althoughは文章の初めのところに置いて、そして正式の場合に用いること。 例：I'd quite like to go out, (al)though it is a bit late. 　　Although it was snowing, it was not very cold. 2. thoughを使うときに、強調の単語を thoughの前に置くことができます。しかし、althoughを使うときに、この用法ができません。 例：Poor though / as he is , he is happy. 　　Child though / as she was, the actress was drawing a crowd. 3. although の後の従文は事実を表します。thoughの後の従文は仮説を表します。 例：Let's start as arranged though it rains tomorrow. 　　He was not unhappy although he had to live alone. 4.though は通常、省略文に使います。 例：Though (he is) alone, he is happy. 5.even if，even thoughにつなぐセンテンスは仮説の語気を表します。 初めて日本語で英語の文法を説明しますので、たぶん内容を理解しにくいかもしれませんが。分かれば、日本語をご訂正してください。

even though の例文はいかのとおりです、ご覧になってください。 He would not reveal the secret even though he knew it.

though and although can't use with BUT they can use with YET