These changes have occurred over a long time span.

这些变化经过了很长一段时间才形成。

《牛津词典》

We protested about the changes for a long time, but in the end we had to submit.

我们对这些变动抗议了很长时间，但最终不得不屈服。

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This might be a good time to reassess your long-term career goals and determine what kind of changes would work best for you.

这或许是一个可以对您的长期职业目标进行重新评估并决定什么样的变迁最适合您的好时机。

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Over long periods of time, these small changes result in the creation of new species.

VOA: special.2009.12.01

After a long time, some of the rock changes to clay.

VOA: special.2009.09.14

Geologic history shows that over a LONG time period that sea level changes by about 65 feet (20 m) for each degree C of change in the ocean.

FORBES: Why Most Forbes Readers Know More About Global Warming than Most Climate Scientists

Dr. Volkmar said it is possible there was in fact an increase in the rate of autism over the long run, because of changes over time such as a greater prevalence of older fathers contributing sperm with small genetic abnormalities.

WSJ: Autism Diagnoses Up Sharply

In 2003 Hansen wrote a widely distributed (but not peer reviewed) paper called Can We Defuse the Global Warming Time Bomb? in which he argues that human-caused forcings on the climate are now greater than the natural ones, and that this, over a long time period, can cause large climate changes.

FORBES: Yes! We Should Defund The U.N.'s Intergovernmental Panel On Climate Change