产品生命周期对营销人员的重要性在于：在产品生命周期的不同阶段需要采取不同的策略。

The importance of the product life cycle to marketers is this: different stages in the product life cycle call for different strategies.

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例如，可以在一系列测试周期内收集性能数据，保存每一周期的数据，并在以后对这些数据进行比较。

For example, you can collect performance data over a series of test cycle runs, keep the data for each run, and compare them later.

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研究员们对女性一个生理周期内的六天进行测验，时间持续六个生理周期或者直到妇女怀孕。

Researchers carried out the tests on day six of each woman's menstrual cycle for six cycles or until the woman fell pregnant.

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Relative to the whole market, It's well known that over periods of multiple decades the market has a tendency to go up.

是和整个市场相关的对吗，我们都知道经过几十年的时间周期,市场会有上涨的倾向。

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And then, just so that you will be literate in the rest of the Periodic Table, if you look at the higher ones, this is how you name them.

然后，你对周期表的,其他方面也都知道了，如果你观察高一点的元素，这是你们叫它们的方式。

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So it looks like not too many more than half of you got this correct, so make sure you can look at your periodic table and figure out how to think about ionization energy in terms of z effective, not just in terms of memorizing what that trend is.

看起来只有一半多一点的人,做对了，所以请大家务必做到能够通过观察周期表,并在考虑电离能时,从有效核电量的观点出发，而不是仅仅依靠记住这个规律。

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