lǎoshī / bǎ / yuèqǔ / cóng / xiǎodiào / gǎichéng / dà diào / hòu / zhěngtǐ / qíngxù / biànde / gèngjiā / kāilǎng

老师把乐曲从小调改成大调后，整体情绪变得更加开朗。

After the teacher changed the piece from a minor key to a major key, its overall mood became more cheerful.