On 13 April, the Titanic was sailing at full speed towards New York. The captain,who had received warnings about icebergs all day, had dismissed the warnigns as they arrived. 

A. had received; had arrived  

B. had received; arrived  

C. received; had arrived  

D. received; arrived  

句子主干为如下：

The captain had dismissed the warnigns as they arrived. 

参考译文：当冰山警告到达的时候，船长毫不理会这些警告。

（备注：不理会动作在到达之前发生，用了过去完成时）

请问选什么？怎么解释句中的had dismissed和arrive的关系？

解答：不会理会这些警告的动作是在达到之前发生，(即在他们达到之前，这位船长久不会这些关于冰山的警告。到达属于过去，在之前就是过去的过去）属于过去的过去，所有用过去完成生态。

答案解析：B 为正确答案

On 13 April, the Titanic was sailing at full speed towards New York. The captain,who had received warnings about icebergs all day, had dismissed the warnigns as they arrived.

参考译文：在4月13日，泰坦里克号正在以全速想纽约行驶，这位整天都收到了有关冰山的警告的船长却不会理会这些警告，当他们达到的时候。

(备注：时间状语从句的主语they指代warnings警告）

(备注：who had received warnings about icebergs all day 属于非限制性定语从句，修饰句子主语"the captain")

补充解答如下

以上句子涉及到以下4个事件,为了更清晰知道谁先发生，谁后发生，我把几个动作重新梳理一下供提问者参考。

A事件：泰坦里克号以全速向纽约航行（2）

B事件：船长整天/一天到晚接到/收到有关冰山的警告（1）

C事件：船长毫不理会/理睬/毫不考虑这些冰山警告（3）

D时间：当关于冰山警告来到/到达的时候（4）

以上ABCD动作按照时间排列顺序为

B收到冰山警告----A全速航行---C毫不理睬冰山警告---D冰山警告到达时候。