(obstetrics, cardiology) vasa previa

one day, 24 hours / the daytime, the period from dawn until dusk / (figuratively) a short period of time / one day, someday, an unspecified day / the first day of the month

(literally) one side / everywhere, all around, the whole area / one viewpoint, one opinion or way of thinking / the front page of a newspaper

for the time being, for the present

the basics, a general idea

underground nuclear test

experimental psychology

experimental study

You should treasure every encounter, for it will never recur.

vicissitudes, the way that the world or a person prospers one day and declines the next