At proper horse races everyone has already studied the form of the horse .
A. behind time
B. in progress
C. in advance
D. in time
网友回答
A. behind time
B. in progress
C. in advance
D. in time
解析：考查词组辨析：. in progress 在进行中， in advance提前， in time迟早，及时，句意是：在赛马比赛中，每个人已经提前对马的情况做了研究。选C。