Others believe that going to classes should be optional for students.

另一些人认为学生应该可以选择去不去上课。

youdao

He said use of the operating system would be optional for all agencies.

他指出所有机构，使用那一操作系统都将成为一种选择。

youdao

Some people believe that university students should be required to attend classes. Others believe that going to classes should be optional for students.

有的人认为大学生应按要求上课，而有的人认为大学生应自行选课。你的看法是？给出原因和具体例子。

youdao

You have a freewill offering--just because someone wants to do this, a freewill offering. And you have a vow offering that would be offered on the successful completion of a vow, for example. And these sacrifices are all entirely optional.

自由祭品--只因为有人想这么干，自由祭品，还有一个誓言祭品,举个例子，一个誓言如果成功达成，便会供奉祭品，这些祭品都是可选择的。

耶鲁公开课 - 旧约导论课程节选

As social change messaging continues to filter beyond marketing and into broader business objectives, communicating respectfully with the 85% of consumers who are female will no longer be optional for advertisers.

FORBES: Gender and Ethics in Advertising: The New CSR Frontier?

The committee has suggested that it should only be optional for a two year transitional period, becoming compulsory thereafter for large cross-border companies, with small businesses being forced to join a common system after a further five years.

BBC: Corporate tax debate

Optional content will be available for purchase.

FORBES: Move up http://i.forbesimg.com t Move down