1.tack用作名词是“图钉,平头针”的意思,转化为动词作“把…钉上,把…固定”解,指用图钉把东西固定下来,以防止其移位。用作及物动词,接名词或代词作宾语。
2.tack还可作“粗缝”解,指不讲究精针细缝的情况下,用针粗粗地缝几针,用作及物动词,接布或衣服之类的名词作宾语。

tack down(v.+adv.)
▲tack sth⇔down
1.用平头钉钉住 fix down with a tack or tacks
Please tack the carpet down.请用平头钉钉住地毯。
2.用粗针缝住 sew down with tacking stitches
She tacked the pleats down.她用粗针脚把褶子都缝住了。
She tacked down a fold onto the sleeve.她在袖子上缝了一个褶。
◇ 用于be ～ed结构
The carpet needs to be tacked down.这地毯需要用平头钉固定住。

tack on(v.+adv.)
1.用平头钉钉上 fix on with a tack or tacks
▲tack sth⇔on
He tacked the sheets of paper on as carefully as possible.他尽量小心地把纸张钉上去。
He tacked the notice on.他把通知钉上了。
We are going to tack the map on.我们打算把这张地图钉上。
2.用粗针缝上 sew on with tacking stitches
▲tack sth⇔on
She tacked the pockets on.她用粗针脚缝上衣袋。
Tack the sleeves on and then sew them up.先把袖子用粗针脚缝上,然后再细细缝好。
3.添加; 附加 add; append
▲tack sth⇔on
She tacked a few words on to the letter her sister had written.她在她妹妹写好的信的末尾加了几句话。
After negotiation, they tacked two new clauses on to the end of the contract.通过协商,他们在合同末尾处又加上了两项新条款。
The customers often tack on a couple of dollars for the tip to the waiter.顾客们经常多给服务员一两美元小费。
◇ 用于be ～ed结构
Another clause was tacked on to the bill.该法案附加了一条新条款。
The bit about help for poorer countries had obviously just been tacked on as an afterthought.关于帮助贫穷国家的那段话显然是事后的想法后来加上去的。
4.紧跟在后 follow closely
▲tack on to sb
I thought you wouldn't mind me tacking on to you.我紧跟着你,我想你不会反对吧。

用作及物动词
▲S+～+n./pron.
He spent the afternoon tacking the pictures.他花了一个下午的时间用图钉固定那些图片。
Where shall I tack the map?我该把这张地图钉在哪儿?
He tacked mosquito-netting over the windows.他在窗上钉纱窗。
The seamstress tacked the two pieces of cloth.女裁缝把那两块布粗缝了起来。

tack还可用作名词,基本意思是“大头钉; 粗缝; 行动方针; 食物”。