Hiya,
1. 調査の結果、事故の原因がわかりました。
Translation given: "Upon investigation, the cause of the accident was identified."
I'm puzzled by the lack of particles or linking words after 調査の結果. Is there something here that is assumed but omitted?
2. 上田さんが中心となって、この研究会を作りました。
Translation given: "The study group was formed centering around Mr Ueda."
I'm having difficulty matching the translation to the original. To me, it looks like a more literal translation would be "(With) Mr Ueda becoming the centre, (we) formed this study group". Is that right?
3. そうでもないけどなあ。
The speaker has been praised for his knowledge of Japan. I'm guessing he's downplaying it and saying something like "No, I don't really know that much". I'm assuming そう + でも + ない + けど + なあ, but I don't understand how this leads to the supposed meaning.
4. ずっと学問を続けていきたいと思っています。
Translation given: "I would like to keep studying as long as possible."
Can I just check that いきたい is from いく, reinforcing the "keep" or "continue" meaning of 続けて?
5. 車にガソリンを入れました。
Translation given: " had gas put in the car."
Where does the sense "had gas put in" come from? Why not " put gas in the car"?