This information is optional, but it's good practice to supply an email address if people want to reach you about the project.

这些信息是可选的，但提供电子邮件地址是比较实际的做法，因为人们可能希望与您取得联系。

youdao

In iterative development, this is much like substituting one optional feature for another as we continually learn about our project and our customer needs.

在迭代开发中，这类似于随着我们不断地了解我们的项目和客户的需求，用一个可选特性来替代另一个。

youdao

I don't like to be dogmatic about things, but this part is not optional.

我这不是搞教条，在这个问题上，其实别无选择。

youdao

The average SAT score is up about 100 points, though Union is now an SAT-optional school, and 25% of the enrolled students didn't submit scores.

WSJ: Frozen Four: Dear Union College: I'm Sorry

Positive action on employing staff will be "entirely optional" under the bill and is "not about quotas".

BBC: Councils 'must consider elderly'

Toyota's 2014 Tundra pickup will come with a standard backup camera, and an optional blind-spot system that can warn a Tundra driver when a car is about to pass.

WSJ: Pickup-Truck Drivers Still Work Hard, but in Comfort