Complex sentence: The second season "Refrain" again makes use of two main pieces of theme music: the opening theme "Boys be Smile" by Suzuyu and the ending theme is by Ayaka Kitazawa.
Split into simpler sentences: The second season "Refrain" again makes use of two main pieces of theme music: one opening theme and one ending theme. The opening theme is "Boys be Smile" by Suzuyu and the ending theme is by Ayaka Kitazawa.