With online course Crazy English has over 20 million students all over China the class through the Internet .
A. attend
B. attended
C. attending
D. to be attending
网友回答
A. attend
B. attended
(答案→)C. attending
D. to be attending
解析：本题考查have sb do/doing；have sth done的用法区别。have sb do 让某人做某事，have sb doing，让某人处于某种状态，have sth done让别人做某事。故选C。