翻译"刚才在办公室里,所以没有立即接您的电话"

I'm sorry to answer your phone call immediately because I was in the office just now.

Sorry for not answering your call immediately for I was in the office just now.

这样最地道

可以将主句中的主语和助动词去除

I'm sorry for not answer your phone call immediately because I was in the office just now.