I let go you optional.

我放手你随意。

youdao

You took an optional course this semester, didn't you?

你这学期选了一门选修课，是吗？

youdao

Somewhere along the line, holiday tipping went from an optional thank-you for a year of services to a Mafia-style protection racket.

一路走来，节日小费从对一年的服务表示感谢的选择变成了黑社会性质的勒索保护费。

youdao

I want to just go over the requirements of the course that really are required, not the optional piece, just so that you understand what my purpose is pedagogically.

我只想跟大家回顾一下,这门课程的必须要求，并非可以自由选择的,这样你们会理解我的目的何在。

耶鲁公开课 - 1945年后的美国小说课程节选

They do have interviews when you apply, but they're optional.

当你申请的时候，他们确实会进行面试。不过也是选择性的。

被学问的自由所迷住 - SpeakingMax英语口语达人

So they're optional, but they're very, very, very highly encouraged that you do these, because this is going to give you practice for the types of problems that are going to be on the exam.

虽然它们是选做的，但是它们非常非常，非常值得你们去做，因为这对你们来说是一次训练,是用来熟悉考试题型的。

麻省理工公开课 - 化学原理课程节选

Share capability, allowing images to be sent wirelessly to an iOS or Android device and edited with the included app -- provided you have the optional Toshiba FlashAir card.

ENGADGET

As it happens, you could configure the Revolve with Windows 7 and you could buy an optional pen to go with it, but obviously, if you'd prefer to use your fingers, you'll have a lot more luck here than you would have with earlier models.

ENGADGET: HP announces the EliteBook Revolve, a Windows 8 convertible for the business crowd (video)

Legal also has crab cakes, shrimp and lots of other optional stuff you can add.

FORBES: Mail Order Meals -- My Favorites