Free boundary
[计] 自由边界
🧩 词语组成解析
free
[fri]
adj. 自由的;免费的;免税的;空闲的;
adv. 免费地;自由地，无拘束地;一帆风顺地;
vt. 免除;释放;使自由;解救;
🗣️ 情景例句
This time draft will fall due at the end of this year.
这张期票年底到期。
But I'll pay. Why not?
但是我付钱啊，不行吗？
This would solve the problem of ventilation, for if a train entered this tunnel, it would draw in fresh air behind it.
因为如果有列火车开进隧道，它就把新鲜空气随之抽进了隧道。