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。

youdao

It is true that these changes take a long time, but not as long as we might expect.

这些变化需要一些长的时间是事实，但不像我们所可能预期的那样久。

youdao

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.

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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In 2003 Hansen wrote a widely distributed (but not peer reviewed) paper called Can We Defuse the Global Warming Time Bomb?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