The plural 's' is not a free form, as it must always be attached to a noun.

表示复数的s不是自由语素，必须附着于名词。

《牛津词典》

You can put them on your desk or clip them to your monitor. They can be attached to your dashboard in your car.

你可以把它们放在你的桌子上或夹在你的显示器上。它们可以安装在你车里的仪表盘上。

youdao

When we talk about a point we are referring to a piece of stone that's worked to a sharp point, in this case probably to be attached to a spear.

当我们说到矛头的时候，我们所指的都是一块被加工成尖头的石块，在这种情况下，这一石块很可能是要接在矛上的。

youdao

Mr.Heppner had his own leg tied back so that a wooden leg could be attached at the knee.

VOA: special.2010.06.11

He reasoned then that the charge, since he could vary voltage continuously but got a discontinuous variation in velocity, his conclusion was that the charge must be discontinuously attached to the droplet.

他推断出电荷，因为他可以不断地改变电压,但是得出了速度是在不连续变化着，他的结论是电荷,是间断地依附于液滴上的。

麻省理工公开课 - 固态化学导论课程节选

The reason they call them coupons is that, in the old days, you used to actually--when you bought a bond, there would be a piece of paper and the piece of paper would have attached to it a lot of little coupons that you would clip.

这里被称作"票息"的原因是,在过去,当你买了债券的时候,会有一张纸,那张纸上附带了许多,你能剪下来的小纸票

耶鲁公开课 - 金融市场课程节选

The connectors fit in either direction, and can be attached and reattached with ease.

ENGADGET

It is hoped the tiny equipment can be attached to several hedgehogs later this year.

BBC: Hedgehog hospital success: Fit-again animals released

The dedicated bayonet lens hood (LH3-01) can be attached to block out extraneous light.

ENGADGET: Sigma DP3 Merrill packs a Foveon X3 sensor and a fixed F2.8, 75mm-equivalent lens