问题补充：
— ? —She’s watching TV at home.
A. How is Mary
B. What does Mary do
C. What is Mary doing
D. How is it going
答案：
A. How is Mary
B. What does Mary do
(答案→)C. What is Mary doing
D. How is it going
解析：情景交际。How is Mary 玛丽怎么样了； What does Mary do
玛丽做什么工作；What is Mary doing玛丽正在做什么； How is it going一切顺利吗。根据答语，她正在家看电视，可知选C。
故选C
