问题补充:
in the war, many children have become orphans(孤儿).
A. Their parents were killed
B. Being killed
C. Their parents killed
D. Killed
答案:
A. Their parents were killed
B. Being killed
(答案→)C. Their parents killed
D. Killed
解析:考查独立主格结构。根据句中逗号可知考查非谓语动词,their parent与kill为被动关系,故用过去分词,选C。