Question

If you are free to walk through out city, please ________ us.
A drop in       B drop in at      C. drop in on

Answer 1

C

試題分析：A.drop in 順路拜訪，B drop in at +地點順路拜訪某地，C.drop in on sb.順路拜訪某人。句中是us，故選C。
點評：完成本題需要了解固定搭配at加地點，on加人。