Covalence
n. 共用電子對數, 共價\\n[化] 共價
??? 情景例句
Especially when it comes to speaking in English and fortunately or unfortunately.
特別是要用英文來演講，不知是幸運還是不幸。
Ill news never comes too late.
壞消息來得快。
In this way, we have learned all that we know of the laws of astronomy,
例如，用這種方法，我們完全掌握了天文學的規律。