，they found that he was gradually recovering.
A. To their much delight
B. To much delight
C. To much their delight
D. Much to their delight
网友回答
A. To their much delight
B. To much delight
C. To much their delight
(答案→)D. Much to their delight
解析：句意：更让他们高兴的是，他们发现他正在渐渐恢复。To one’s delight令人感到高兴的是，much是程度副词，放在这个短语前起修饰作用,这个短语中的物主代词与句子的主语保持一致，根据句意故选D。