Keystone state
na. 宾夕法尼亚州的浑名\\n
🧩 词语组成解析
keystone
[['ki:stəun]]
n. 拱顶石, 楔石, 重点
🗣️ 情景例句
Who jammed the photocopier, again?
谁又把复印机卡住了？
He operates the crane.
他在操纵起重机。
the graphic record shows three waves arriving one after the other at short intervals.
曲线纪录就能显示出前后相间的这3种地震波。