—My mother is ill.—A. OK.B. Too bad.C. Thank you.D. I’m sorry to hear that.

问题补充：

—My mother is ill.

—

A. OK.

B. Too bad.

C. Thank you.

D. I’m sorry to hear that.

答案：

A. OK.

B. Too bad.

C. Thank you.

(答案→)D. I’m sorry to hear that.

解析：句意：我母亲生病了。OK.好的；Too bad. 太坏啦；Thank you. 谢谢你；I’m sorry to hear that听到这我感到很不安。根据语境该选D。