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：
非谓语动词作状语的用法。根据前半句的While watching television推断主语必须是“观看电视”这动作的发出者，即we；同时主句有have sb. do sth.的句型，省略了to的不不定式做宾补。