47. We appreciate your patience and please _____ that we will do everything in our power to _____ that this type of error does not occur in the future.
(A)assure.....be ensured
(B)be assured....be ensured
(C)be assured....ensure
(D)assure....ensure。

答案：登入後查看
統計： A(1), B(0), C(5), D(1), E(0) #2394613