The last one I saw was called 'Spelling' and it was a kind of quiz where the competitors had to spell difficult words fast and finish at a certain time.

我看到的最后一个叫做“拼写”，这是一种测试，参赛者必须快速拼写困难的单词，并在某个时间完成。

One day at a certain time, to return.

某日某时，旧地重游。

The concrete will set after a certain time.

过一段时间之后，混凝土就会硬化。

Why did a step not execute at a certain time?

某一次，一个步骤为何没执行？

Don’t focus on exercising at a certain time .

不要专注在锻炼到某个特定的时间。

Social events can be fun within a certain time frame.

在一定的时间范围内的社交活动可以很有趣。

Animals can be conditioned to expect food at certain time.

可以训练动物定时等待食物。

Not until you are in a certain time or certain occasion that you feel the truth.

不到一定的时间场合。

Firstly, make a review plan with certain contents of subjects at a certain time.

首先，制定复习计划，确定在某段时间里复习课程的具体内容。

But they are always in a certain place, a certain time, mutual envy of each other.

但他们却总在某个地点，某个时间，互相羡慕着对方。