问题补充：
his bike is lost? He has to go to school on foot.
A. What if
B. How about
C. Can you tell me
D. I don know
答案：
(答案→)A. What if
B. How about
C. Can you tell me
D. I don know
解析：What if假使……将会怎么样；How about你认为……怎么样；Can you tell me你能告诉我吗；I don know我不知道。根据下文，他不得不步行去学校。可知上文句意为：假使他的自行车丢了将会怎么样？故选A。
