93. It is our job to be certain that the product conforms exactly to the custome r's _____. (A)specifications (B)dimensions (C)estimation (D)arbitration 。

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