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
I'm so sorry.
很抱歉。
Her parents died when she was a baby and she was raised by her grandparents.
她很小的时候，父母就死了，是祖父母把她带大的。
Since that time, various types of hovercraft have appeared and taken up regular service.
从那以后，各种各样的气垫船出现了，并开始了定期航行服务。