Actinium series
[化] 锕系(指89~103号元素)
🧩 词语组成解析
n. 锕\\n[化] 锕Ac
🗣️ 情景例句
Thank you. Yes, actually Mary and I have been planning this for some time.
谢谢。其实玛丽和我已计划了很久。
They had to cut down a lot of trees to make room for farms.
他们为了为农场增加空间不得不砍倒很多树。
At this time, the man downstairs was trying to sleep.
这时楼下人正试图入睡。