when deeply absorbed in work,——he often was,he would forget all about eating.

问题描述:

when deeply absorbed in work,——he often was,he would forget all about eating.
空格处填的which是作表语吗?

正确,he was做后置定语,was是系动词,所以是he was which系动词后都是表语,感官系动词也包括:taste smell……