While watching television, .
A. the doorbell rang
B. the doorbell rings
C. we heard the doorbell ring
D. we heard the doorbell rings
网友回答
A. the doorbell rang
B. the doorbell rings
(答案→)C. we heard the doorbell ring
D. we heard the doorbell rings
解析：考查非谓语动词与句子主语一致。