Pre-op
abbr. preoperation 空转, 试运转; preoperational 试运转的
🧩 词语组成解析
abbr. 炼油工程师（Petroleum Refining Engineer）
观测所\\n[计] 操作, 运算, 算符
🗣️ 情景例句
No problem.
小事一桩。
I used to take a walk in the early morning.
我过去常一大早出去散步。
Between 1850 and 1910 the bison population is thought to have fallen from 60 million to just a few hundred.
人们认为，在1850年到1910年之间，野牛的头数从6，000万头降到只有几百头了。