阿摩線上測驗
23. _____, the machines stopped working.
(A) Had been leaving unattended
(B) Have left unattending
(C) Having been left unattended
(D) Had been left unattending
答案：登入後查看
統計： A(44), B(15), C(92), D(59), E(0) #3430659
統計： A(44), B(15), C(92), D(59), E(0) #3430659
