I do not know the music theory, so I can not say what is the chord.
2
若要歌唱你必须先张开嘴,你必须有一对肺叶和一点儿乐理知识。
To sing you must first open your mouth. You must have a pair of lungs, and a little knowledge of music.
3
进入大学以来,我选修了大学音乐,对音乐乐理知识基本上能够了解,甚至可以自学。
Since I attended college, I took College Music as elective course, which provided me a general understanding of basic knowledge, even the ability to teach myself further.