My time spent in the library was very productive.

我花在图书馆的时间很有收获。

《牛津词典》

The concern seems to be that open advocates don't spend their time being as productive as possible.

问题似乎在于，公开的提倡者不会把时间花在尽可能高效的事情上。

youdao

It is probably more productive—for the time being, at least—to engage at the lower and midlevels.

在目前更有成效的也许是在中下层的接触。

youdao

People who bully spend less time on productive work.

VOA: special.2011.03.25

Travel time can be productive time.

FORBES: Why Business Aviation?

Like most monitoring programs, it also allows Mr. Daniels to see whether all his employees, including 16 office workers and 24 who work from home, are using their computer time in productive ways.

WSJ: 'Working From Home' Without Slacking Off

After the recession left millions jobless, some economists said they hoped that in lieu of work, Americans would spend more time on productive activities, such as volunteering or exercise, said Princeton economist Alan Krueger.

WSJ: Leisure Tops Learning in Survey