Sigma bond
[化] σ键
🧩 词语组成解析
[计] 求和\\n[医] σ(希腊文第十八个字母)
🗣️ 情景例句
He took care of my daughter
我女儿曾受他照顾，
Lovers live by love, as larks live by leeks.
情侣靠爱情生活，正像云雀靠韭葱生活一样。
My grammar is improving, but I find idioms and useful expressions hard to learn.
我的语法在进步，但我发现习语和有用表达很难学。