1911年4月，______领导的同盟会为推翻清王朝的统治，在广州起义失败，战役牺牲的烈士营葬于黄花岗，此次起义因此又称黄花岗起义。

A．孙中山、黄兴
B．孙中山、黎元洪
C．黄兴、黎元洪
D．黄兴、徐世昌

I was giving a talk to a large group of people, the same talk I（）to half a dozen other groups before.

A.was giving

B.am giving

C.had given

D.have given