n.敲平头顶的人；敲平头钉器
It would be unwise to change tack now. 现在改变方针是不明智的。
Tack the folds down before you sew them firmly into place. 先用大针脚将褶子松松地缀住，然后再将其缝纫到位。
I hammered a tack into the wall and hung a small picture from it. 我在墙上钉了一个图钉，然后在上面挂了一张小图片。
The speaker suddenly changed tack and left us all rather confused. 演讲人突然改变了论调，把我们都搞糊涂了。
His brother is sharp as a tack; he got100 on every test. 他弟弟十分聪明伶俐，每次考试都得100分。
n.攻击者；抨击者
n.栈式存储器；推积机；堆垛机；堆积者
