All the President’s Men ____one of the important books for historians who接上面的提问:study the Watergate Scandal.A.remain B.remains C.remained D.is remaining请问:为什么选B啊?为什么是单数谓语啊?望答复,

All the President’s Men ____one of the important books for historians who接上面的提问:study the Watergate Scandal.A.remain B.remains C.remained D.is remaining请问:为什么选B啊?为什么是单数谓语啊?望答复,
All the President’s Men ____one of the important books for historians who
接上面的提问:study the Watergate Scandal.A.remain B.remains C.remained D.is remaining
请问:为什么选B啊?为什么是单数谓语啊?望答复,

All the President’s Men ____one of the important books for historians who接上面的提问:study the Watergate Scandal.A.remain B.remains C.remained D.is remaining请问:为什么选B啊?为什么是单数谓语啊?望答复,
remain 为不及物动词,并且主语为一本书的名字（all the president's men）,故用单数.此外,表示存续的状态,一般用一般时态（过去时态或现在时态）.选择b or c都可以,关键是看作者要表达哪个含义.

主语是一本书的名字，也就是一本书做主语。