The old couple are living for their only son works abroad after graduation.A. on their own

问题补充：

The old couple are living,for their only son works abroad after graduation.

A. on their own

B. of their own

C. separately

D. particularly

答案：

(答案→)A. on their own

B. of their own

C. separately

D. particularly

解析：“惟一的儿子在国外工作，因此这对老年夫妇独自生活。”on ones own“独自地”;of one’s own“某人自己的”，C、D两项与句意不符。