Monotube
单管的, 直流的
🗣️ 情景例句
I have to sign copies of my book for a lot of people
我还必须为许多人在我的书上签名
Where is the ticket office?
售票处在哪儿？
Mum slept almost the whole way.
妈妈在整个途中几乎都在睡觉。