Question

His bike is broken, so he ________ walk to school．

A. have to
B. has to
C. must
D. may

Answer 1

答案B
因为自行车坏了，所以他“不得不”(has to)，而不是“必须”(must)或“可以”(may)走着去上学；主语是第三人称单数，故选B。