Lhs
产生式规则左部
🗣️ 情景例句
What are you up to?
你在忙些什么？
Ouch! I fell down and cut my knee!
好痛呦！我跌倒割伤了膝盖！
They also have the disadvantage of being an expensive form of transport.
飞机另一个缺点是昂贵。