Squelette
翼形中线(弧线), 剖面中线
🗣️ 情景例句
Nice to meet you, Mr. Baker.
很高兴见到你， Baker先生。
Then, all of a sudden, it became cloudy and began to rain.
可是突然天就变了，乌云密布并下起雨来。
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。