某些课程是必修的，其他是选修的。

Certain courses are compulsory, others are optional.

《牛津词典》

大学里有的课程是必修的,有是是选修的.

Some courses in college are required while others are optional.

youdao

大学里有的课程是必修的，有是是选修的。

Some courses in college are required while others are optional.

youdao

Now those of you who have taken English 125 or any course that has asked you to read Spenser will recognize almost instantly I think, I hope, Milton's literary depth.

你们中选修英文125或者其他让你们读斯潘塞的课程,的人应该能立刻认识到，弥尔顿的文学功底很深。

耶鲁公开课 - 弥尔顿课程节选

The ironic fact is, because the New Testament is considered more important by people, there are a whole lot more people who take my New Testament classes than go over to the Classics Department and take a course in Plato.

讽刺的是，由于人们认为新约更重要，所以在我新约课堂上的人,远远多于,在古典学系选修柏拉图的人。

耶鲁公开课 - 新约课程节选

But I'm also proud of my alumni in this course who are not in the world of finance.

同时我也很为那些选修过这课的,却不在金融领域工作的毕业生们自豪

耶鲁公开课 - 金融市场课程节选