Preoxidation
预氧化
🗣️ 情景例句
No. It's not.
不是。
How much is it by air mail?
航空信要多少钱？
Yesterday the firemen examined the ground carefully, but were not able to find any broken glass.
昨天，消防队员仔细查看了地面，但未能发现碎玻璃。