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
C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。