Preverb
句首助动词, 前动词(即移至句子第一个位置上的助动词)
🗣️ 情景例句
Anybody home?
有人在家吗？
Yes,I had breakfast two hours ago.
是,我2小时以前吃了早餐。
That's right.I drove it into a lamp-post.
是啊。我把汽车撞在电线杆上了。