Boundary trace
[计] 边界道
🧩 词语组成解析
trace
[tres]
vt. 跟踪，追踪;追溯，探索;探索;查找;
vi. 沿着一小径或道路前进;可以追溯的;
n. 痕迹，踪迹;微量，极少量;[植]（脉）迹;痕迹;
trace(draw)→回溯
🗣️ 情景例句
This is the big moment.
这可是关键时刻。
After dinner, they adjourned to the study to talk.
晚饭后，他们到书房谈话去了。
'Oh dear,' said the conductor suddenly.
“哎呀，”售票员突然说，