Hegar's operation
[医] 黑加氏手术(会阴缝术)
🧩 词语组成解析
🗣️ 情景例句
How much are the dues?
会费多少？
There is no royal road to learning.
治学无坦途。
It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951;
这个频率是空间氢原子释放的自然频率，是在1951年被人类发现的。