clock is ticking, the

The time (for something to be done) is passing quickly; hurry up. For example, The clock is ticking on that project. This allusion to a stopwatch is often used as an admonition to speed something up. It also is used in more specific form-- one's biological clock is ticking--meaning that a woman may soon be too old to bear a child, as in Her biological clock is ticking--she just turned forty.