It's a proper time to start it when a unit is over.

一个单元结束时是开始这件事的合适时间。

youdao

I'll clarify my stand at a proper time.

我将在合适的时候澄清我的立场。

youdao

There is a proper time for every activity.

每项活动都有适当的时间。

youdao

Republican lawmakers say Democrats are trying to push through a bill without enough time for proper Congressional scrutiny.

VOA: standard.2009.07.29

There will be a proper time to discuss such things.

FORBES: Roof Collapse Could Be End Of NFL In Minnesota

Mr. ANTHONY HAMILTON (Musician): There's a proper time and place for everything, and once you put so much time into it, you'd be a fool to turn around and walk away from it, 'cause I tasted it.

NPR: Anthony Hamilton: 'Ain't Nobody Worryin'

Trying to conserve her energy, she barely qualified for the final ("Definitely a little bit of a scare, " she said.) She didn't have enough time for a proper cool-down, so as her U.S. teammate Ryan Lochte swam to a fourth-place finish in the men's 200-meter freestyle, Franklin swam slow, lonely laps by herself in the adjacent diving well, trying to lower her heart rate and ready for her main event.

WSJ: 2012 London Olympics: A Priceless Gold for Missy Franklin - Jason Gay