She says one possibility is a decrease in the number of school nurses during the period they studied.

VOA: special.2009.08.06

And it turns out that simply by counting the number of those spikes that occurs at a period of time.

随后，只要数一数在一定时间内,产生的尖峰脉冲的数量。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

Suppose someone has a contract that promises to pay an amount each period over a number of years.

假设某人有一份合约,承诺在数年内的不同时段内分开支付

耶鲁公开课 - 金融市场课程节选

In a similar period starting 18 months after the ban, the number was 237.

VOA: special.2009.01.07

By the end of the period there was an unprecedented number of new religious groups.

在这段时期末,出现了空前多的新宗教派系。

耶鲁公开课 - 弥尔顿课程节选

Over a four year period, the number of regular opium users jumped 53 percent.

VOA: standard.2010.06.23

Now what we do is to record the number of those action potentials in some period of time, and plot them on the graph below.

现在，我们要做的是记录,在一定时间内可能做出的动作，在图表中设计出来。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选

A recent UN report found the number of civilians killed increased by 24 percent in the first six months of this year compared to the same period in 2008.

VOA: standard.2009.08.07

Okay, well the interesting thing is, you guys in a very short period of time generated a number of ideas about what this could be.

好,有意思的是,大家在很短时间内,猜出了很多种东西

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

So, for example, we can move to the next periods in the periodic table. When we talk about a period, we're just talking about that principle quantum number, so period 2 means that we're talking about starting with the 2 s orbitals, period 3 starts with, what we're now filling into the 3 s orbitals here.

我们可以移至周期表的下一个周期,当我们讨论一个周期时，我们仅仅讨论,周期3以我们所填充的3s轨道，开始填充所以周期2意味着,我们从2s轨道谈起，周期3以我们所填充的3s轨道开始填充。

麻省理工公开课 - 化学原理课程节选

There were probably a number of firms that, over that ten-year period, went out of business.

在这10年间,可能有很多企业已经破产

耶鲁公开课 - 金融市场课程节选

The return, of course, in any given time period is the percentage increase in the portfolio; or, it could be a negative number, it could be a decrease.

当然了，收益率是一定时间内,投资组合的增长率;,也可能是一个负数，表示负增长。

耶鲁公开课 - 金融市场课程节选

I bought a number of two-period bonds such that the value of my purchase exactly equals the proceeds that I get from shorting the one period bond, so I've made a zero wealth transaction.

我买入了一定数量的两年期债券,其成本刚好等于我卖空,一单位一年期债券获得的资金,我做的是零成本交易

耶鲁公开课 - 金融市场课程节选