阿摩線上測驗
21. Please give us a call ________ you arrive at home. We want to know that you're safe.
(A) just
(B) must
(C) once
(D) twice
答案：登入後查看
統計： A(23), B(1), C(65), D(2), E(0) #666966
統計： A(23), B(1), C(65), D(2), E(0) #666966
