懂了, by Tank (吕健中), is a song from the soundtrack of 花样少年少女 (Hana Kimi), a popular Taiwanese idol drama. Tank, a singer-songwriter from Taiwan, wrote the music and co-wrote the lyrics with 徐旻铃.
I’m fascinated by songs that undergo modulation (that is, changes from one key to another within the song), although the concept of modulation has become less of a mystery to me now. 懂了 is one such song and this was one motivation for me to figure out the chords for it apart from the fact that I liked this song when it first came out. So it was satisfying for me to be able to figure out this song from intro to ending.
Listen to the song: