对所有学生来说，英语是必修的，但艺术和音乐是可选的。

English is required for all students, but art and music are ___optional.

关于可选课程，建议口语和听力、计算机研究和商务英语适合拍摄。

Referring to ___optional lessons, it was recommended that Speaking and Listening, Computer Studies and Business English are suitable for filming.

参加研讨会是可选的，所以你可以决定是否来。

Attendance at the workshop is ___optional, so you can decide whether to come.