Question

________ Mary________ Jack is listening to the report carefully, because they are both interested in it very much.

A.Not only, but also B.Either, or C.Both, and

Answer

A

【解析】

句意：不仅玛丽而且杰克都在认真听报告，因为他们都非常感兴趣。

考查连词。not only...but also...不仅……而且……，连接两个主语时谓语动词就近原则；either...or...或者……或者，连接两个主语时谓语动词就近原则；both...and...……和……都，连接两个主语时谓语动词用复数形式；根据is可知主语是单三，排除C；根据“they are both interested in it very much他们都非常感兴趣”，所以他们两个都认真听；故选A。