be doing time at

You would be doing something worthwhile and at the same time learning about the reality of being homeless.

你将会是在做一些有意义的事情。与此同时，你也将了解无家可归的无奈。

Feeling like you're floating through a cosmic wonderland might be exciting for a while, but doing that for weeks at a time can be very unsettling.

想象下自己飞梭在美妙的宇宙中，也许你会兴奋一阵子，但是如果一次就让你持续数周时间会令你深感不安。

In other cases, doing things at compile time is less feasible, but savings can be made by avoiding repeated execution at run time.

在其它情况下，在编译时执行操作不太可行，但执行保存可以避免在运行时执行重复操作。