P-r interval
[医] P-R间期(心电图)
🧩 词语组成解析
🗣️ 情景例句
on the school board,
在联合校董会中
Packing will help push the sales.
包装有助于推销产品。
A short time before, great trees had covered the countryside for miles around.
就在不久之前，参天大树还覆盖着方圆数英里的土地。