those指代immune problems antibodies,在没有上下文的情况下,可以认为work前省略了was.
Back in the ,probably I would say this,the beginning of the 70s and into the early 80s,介词短语做时间状语,probably I would say this,插入语,可以不要.quite a bit of work was done on spontaneous miscarrige in relation to several aspects of what we called "immune problems antibodies" and related to those are the blood groups.是简单句.主语quite a bit of work,谓语动词 was done .on spontaneous miscarrige in relation to several aspects of what we called "immune problems antibodies" and related to those are the blood groups是状语.