问题补充：
--- I haven’t seen Mary recently. And you?
--- Me neither. I’m afraid she to her experiment for too long a time.
A. is devoting
B. was devoted
C. has been devoting
D. has been devoted
答案：
A. is devoting
B. was devoted
C. has been devoting
(答案→)D. has been devoted
解析：考查时态。固定词组be devoted to致力于。根据上下文可知我最近没有空间Mary,是因为她致力于做实验。使用完成时表示过去发生的事情对现在的影响。
