At once...and...
既...又...
🧩 词语组成解析
at
[æt]
prep. （表示位置）在;在（某时间或时刻）;以，达; 向，朝;
n. 阿特（老挝辅币单位，100 阿特 = 1 基普）;
🗣️ 情景例句
(a foreigner) Is that a special day?
（一个外国人）是一个特殊的日子吗？
He didn't visit this country on the tour.
他在旅行中不拟访问这个国家。
It later became apparent that rabbits were developing a degree of resistance to this disease,
后来，明显看出，兔子对这种疾病已产生了一定程度的免疫力，