_There remains_ a certain doubt among the people as to the practical value of the

there remains是there is的一种特殊形式. 类似的结构还有there stands/lies/lives等.其中remain, stand, lie, live等都是系动词,它们与there在一起,都可以翻译成“有”.这种结构的句子中的主语都是there be/remain/lie/stand/live后面的名词或相当于名词的短语.如例句的主语就是a certain doubt among the people as to the practical value of the project.
如果用it remains,那么remains就是实义动词了,a certain doubt among the people as to the practical value of the project就是宾语了,那么it 就指代不明了.
句意：这个项目的实用价值如何,在人们当中还有一定的疑问.
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