Perioidic system
[机] 周期系
🧩 词语组成解析
🗣️ 情景例句
Hang in there. things will get better.
坚持住，情况会好起来。
Yes, but I'd rather not have done it.
是的，但我宁可没有这样做。
He did not know from which part of Africa his ancestor had come.
他不知道祖先来自非洲的什么地方。