While watching television .A. the doorbell rangB. the doorbell ringsC. we heard the doo

问题补充：

While watching television, .

A. the doorbell rang

B. the doorbell rings

C. we heard the doorbell ring

D. we heard the doorbell rings

答案：

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。