He absorbed himself so entirely to his research that he made himself ill.A. unfortunatelyB

问题补充：

He absorbed himself so entirely to his research that he made himself ill.

A. unfortunately

B. purposefully

C. hopefully

D. eventually

答案：

A. unfortunately

B. purposefully

C. hopefully

(答案→)D. eventually

解析：句意：他全身心地投入工作，终于病倒了。eventually (=in the end,at last)最后；终于；unfortunately不幸的；遗憾地；hopefully 怀有希望地；purposefully有决心地，坚定地。