The days get shorter after the Summer Solstice.

过了夏至， 天就开始变短。

《新英汉大辞典》

When autumn comes, days get shorter.

秋天来临的时候，白天变短了。

youdao

The days get longer and the nights get shorter.

白天变长了，黑夜变短了。

youdao

They produce colorful blooms when days get shorter and nights get longer.

VOA: special.2010.06.29

People lived shorter lives and so they didn't get far enough into the age span to suffer from the chronic diseases that people are suffering more today.

当时的人寿命比较短所以他们,活不到现代人那么长,长得足以患上那些慢性疾病

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

But with other budget cuts, such as Medicare and welfare, becoming so painful, the pole may get shorter.

CNN: Budget cutters take hard look at Social Security - Sept. 27, 1995

Jones is betting that as technology cycles get shorter, manufacturers will favor nimble suppliers who can help them figure out how to churn out smaller, faster chips.

FORBES: Suddenly Sexy

Every time a cell divides, its telomeres get shorter.

ECONOMIST: Ageing