He stooped down, cut the stem for her with his knife and handed her the flower.

他弯下腰，用刀替她割下花茎，然后把花递给她。

《柯林斯英汉双解大词典》

The stem for better is better.

better 的词干是 better。

youdao

The stem for good is good.

good的词干是good。

youdao

In March, President Obama ended restrictions on the use of federal money for research using human embryonic stem cells.

VOA: special.2009.04.07

A capability for asymmetric division and the production of cells that become differentiating more mature cells, those are properties of stem cells.

能够完成不对称分裂,以及产生细胞,并分化成为一些更成熟的细胞,这些是干细胞的性质

耶鲁公开课 - 生物医学工程探索课程节选

What are stem cells used for exactly?

干细胞到底是用来做什么的？

关于干细胞的研究 - SpeakingMax英语口语达人

One selling point: Instead of an adjustable, long stem for a bike seat, Scott's seat posts are cut and bolted tight (by dealers in the store) to fit the rider.

FORBES: Spinning Wheels

And yet, most of us cannot afford to purchase a wine stem for every grape varietal (currently Riedel offers wine glasses for everything from Chardonnay and Pinot Noir to Riesling and Cabernet Sauvignon).

FORBES: What Is The Best Wine Glass For Enjoying Wine?

The fine distinction in the NIH policy created the possibility of a private market for supplying stem cells for publicly funded research.

CNN: Looking for middle ground in a minefield