Acknowledger
n. 认收开关；了望装置
🗣️ 情景例句
That is some history!
这阅历了不得，
Ok, bye-bye.
好吧，再见。
Fortunately, however, ancient men made tools of stone, especially flint,
然而， 幸运的是，远古人用石头制作了工具，特别是用燧石，