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

He says about 13 U.S.troops will be attached to each Afghan battalion of about 500 soldiers, and also to police units.

VOA: standard.2009.03.31

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

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

The maps are to be attached to a long-overdue presidential decree meant to formalise the moratorium.

ECONOMIST: Banyan