Abv
abbr. 在上面（above）
🗣️ 情景例句
What subject did you major in university?
你在大学主修的科目是什么？
A standard one. Replacement during the first year if all rules for proper use have been followed.
有一个原则，如果在一年内符合各种使用规定，就可更换。
This would solve the problem of ventilation, for if a train entered this tunnel, it would draw in fresh air behind it.
因为如果有列火车开进隧道，它就把新鲜空气随之抽进了隧道。