Hb
abbr. [军] 厚膛壁身管（Heavy Barrel）
📖 牛津释义
HB
abbr
缩写 = (of lead used in pencils) hard black (ie medium hard) （指铅笔芯）硬黑（即硬度适中）
an HB pencil 一支HB的铅笔. Cf 参看 B, H.
🗣️ 情景例句
and remember the meaning of Thanksgiving.
来追忆一下感恩节的意义。
I don't seem to have any luck today.
我今天运气不好。
that given a planet only approximately like our own, life is almost certain to start.
如果设想有一颗行星和我们地球的情况基本相似，那几乎肯定会产生生命。