There is not a quit difference between 教師 and 先生. I'm working as an English and I use both. 教師 sounds a little official and focuses on being a teacher as a job, and 先生 sounds more general and focuses on his/her personality. But the difference is so tiny bit that you don't have to worry about it. がんばって！！

わたしは がくせい です わたしは だいがく いちねんせい です わたしは こんぴゅーたーさいえんすを べんきょうしたいと おもっています わたしは ゲームが すきです わたしは にほんに りょこうしたい です わたしは にゅーよーくで うまれました あにめを じまくなしで みたいので わたしは にほんごを べんきょうしたいと おもっています。 If you need kanji version as well, let me know :)

「あー、なるほど！」　Wow! I see 「知らなかった！」 I didn't know that 「めっちゃおもしろいね」　That's very interesting (casual) 「とてもおもしろいですね」 (formal) 「おしえてくれてありがとー」 Thank you for explaining (teaching) to me (casual) 「えー、さんきゅー！」(casual) other expressions ほうほう *pronounce like ho-ho- (deeply interested) ふむふむ(otaku) なるほど is good word to express your interest. I often say it, too. If you have any question, I always help you :)

How about studying with a kanji textbook which is targeted at Japanese first grade students(5~6 years old)? Even native Jaapnese speakers have to learn knaji when we are children. We start learning kanji from elementary school, and most of us keep learning until we graduate from high school. And still people sometimes struggle with kanji after grown up, especially writing. Moreover, starting from easy kanji is essential because kanji is like a puzzle which has lots of pieces. For example, 働く（はたらく, to work） looks so complicated, isn't it? But every part of it is not so difficult. The left part is 人（person） and the other part is 動く（うごく, to move.） 動く also consists of two parts, one is 重い（おもい, heavy） and the other is 力（ちから, power） So to work is like [person + heavy + power], and it makes sence, doesn't it? Not all kanji is like that(to know「知」= arrow「矢」+ mouth「口」 it doesn't make sence), but starting from easy kanji with kanij textbook for first grade students is an effective way to learn kanji. Most kanji textbooks for kids are cute, colorful, and interesting. And they have lots of pictures and are written in hiragana, so it is easy even for foreigners to understand. I think you can buy on amazon or other internet sites. I think you should learn like a kid :) I'm sorry my English is so bad, but I hope that the answer will help you find a good way to learn Japanese :)

大学の学長ともあろう人　means " a person like a president of the university" It has a connotation that a president of the university shouldn't do anything bad. 原爆を落とすなどという（許すべからざる）行為　means "such a (unforgivable) things like drop an atomic bomb" the content of the puestion sentence is a little awkward to talk about, though....

I would say　「すぐに翻訳を送ります」or 「翻訳したものがすぐに届きます」 It depends on the context. Even simple sentences sometimes are very difficult to trancelate directly. 「翻訳したものがメールで届きます」「翻訳をすぐにメールします」「英語訳がすぐに来ます」 Choose whichever you like haha

シャツは一枚だけある。　シャツが一枚だけある。Both are correct. But meaning is slightly different. シャツは一枚だけある sounds like it is an answer for a question like "how many shirts do you have?" If you want to mean just like "There's only one shirt" you say シャツが一枚だけある。 Even for fluent Japanese speakers, the problem of "は and が" is so tough. I, native Japanese speaker, can use them collectly, but I don't know the rules of them. Anyway, I'm glad that many foreign people like you are learning Japanese. :)