问题
选择题
O'Neal works hard. He is often seen _______ heavily before his teammates have even arrived at practice.
A．sweated
B．to be sweated
C．sweating
D．being sweated
答案
答案：C
非谓语动词的考查是本题的目的。see somebody doing表示看见某人一直正在干某事，题干中只是
将主动变成了被动。