Septavalency
(=septavalence)[化]七價
??? 情景例句
And good luck! I've got to go.
祝你好運 我得走了。
I'm sorry, but it's just not possible.
抱歉，實在是愛莫能助。
Cave exploration, or pot-holing, as it has come to be known, is a relatively new sport.
洞穴勘查——或洞穴勘探——是一項比較新的體育活動。