We all have trouble and sound less good at certain times.
The house and park are open to the public at certain times of the year.
Maybe it only works at certain times of the year.
At certain times in their development young people will face particularly difficult problems.
Why does it become so important at a certain time in life to know where we come from?
"But they are under no pressure to do things by a certain time."
Do I take it at a certain time of day?
You don't have to come home at a certain time.
At certain times, the house will be open to the public.
If he doesn't follow up and call by a certain time?