The most promising technique for reducing city traffic is called congestion pricing, whereby cities charge a toll on entering certain parts of town at certain times of day. (scientificamerican.com)
Photography is not always a continuous career, and many photographers have produced bodies of works at certain times in in their lives, and then not returned to the medium. (turnercontemporary.org)
That setup allowed the scientists to test whether different species were attracted only at certain times of day. (sciencedaily.com)