The hard, unglamorous preparation that has to be done before the real thing can happen. It comes from digging: before you plant anything, someone has to break up the ground. So spadework is the digging part of a job — the phone calls, the reading, the small meetings, the paperwork — done early, done by hand, and usually not seen by the people who show up later for the exciting part. It is an uncountable noun, so you say 'a lot of spadework', 'much of the spadework', never 'a spadework' or 'two spadeworks'. It lives most naturally with 'do': 'do the spadework'. You will hear it in news and business writing more than in daily conversation — 'years of diplomatic spadework' before a treaty, 'the spadework of research' before a book gets written. There is usually a small note of respect hidden in it, and sometimes a small complaint: the speaker often means someone did the hard part and someone else got the credit. It is not the same as 'groundwork', though the two are close. Groundwork is the foundation you build on, and can sound rather grand; spadework keeps the smell of dirt on it, and points more at the labour than at the structure it supports.

前置的苦工、打底的準備工作（尤指瑣碎、耗時、不受注意的那部分）