B.t.u.
abbr. 英国热量单位（British thermal unit）；英国商务部单位（Board of Trade Unit）
🗣️ 情景例句
So am I.
我也很遗憾。
Did you repair this yourself?
你自己亲自修理这个？
both men were genuinely sorry that they had to leave.
这二位不得不离开那个荒岛时，还真的感到遗憾呢！