On our way home our bikes so we had to walk home.A. is brokenB. was brokeC. broke downD.

问题补充：

On our way home, our bikes, so we had to walk home.

A. is broken

B. was broke

C. broke down

D. breaks down

答案：

A. is broken

B. was broke

(答案→)C. broke down

D. breaks down

解析：句意：在我们回家的路上，我们的自行车坏了，所以我们不得不走着回家。Break down意为“机器坏了，出毛病了”，根据后面的句子时态可知，应该用过去时态；故选C。