P-r interval
[医] P-R间期(心电图)
🧩 词语组成解析
🗣️ 情景例句
How many days will it take for my mail to reach its destination?
我的信件到达目的地要用几天？
A person must strain one's ears to hear a wild animal in the forest.
在森林里，人类必须对野兽竖起耳朵才行。
Sorry to hear that.
听到这个消息我很难受。