It's just some random chunk of four bytes that happens to be available at this point in time, but I can put something there.

只是一些随机的四字节的内存块,在这里是可以使用的，但是我可以在那里放置东西。

哈佛公开课 - 计算机科学课程节选

Right now what you want to make sure is that there is a time that's available... right now all the times are available... but that there is a time that works for you.

现在你需要确定的,是你有现成的时间。,目前所有的时间都是现成的。,而且要有你可以使用的时间。

耶鲁公开课 - 死亡课程节选

Once you have registered, if some other slots become available that weren't previously available, I gather you'll be sent some sort of email by the system, in case some other time would be better for you.

一旦你注册了，之前的有些项目,就可用了，系统会用邮件方式向你发送，让你的时间更方便。

耶鲁公开课 - 死亡课程节选