The two friends on the Internet for three hours, and they would go on till the next morning.
A. had been chatting
B. had chatted
C. were chatting
D. has been chatting
网友回答
(答案→)A. had been chatting
B. had chatted
C. were chatting
D. has been chatting
解析：句意：这两个朋友已经上网聊天3个小时了，而且还将继续到第二天早上。这个过去的过去一直在进行并且将延续到动作当然应该用过去完成进行时来表达。