As many people hit middle age, they often start to notice that their memory and mental clarity are not what they used to be. We suddenly can’t remember (1)_____ we put the keys just a moment ago, or an old acquaintance’s name, or the name of an old band we used to love. As the brain (2)_____, we refer to these occurrences as “senior moments.” (3)_____ seemingly innocent, this loss of mental focus can potentially have a(n) (4)_____ impact on our professional, social, and personal (5)_____.

     Neuroscientists, experts who study the nervous system, are increasingly showing that there’s actually a lot that can be done. It (6)_____ out that the brain needs exercise in much the same way our muscles do, and the right mental (7)_____ can significantly improve our basic cognitive (8)_____. Thinking is essentially a (9)_____ of making connections in the brain. To a certain extent, our ability to (10)_____ in making the connections that drive intelligence is inherited. (11)_____, because these connections are made through effort and practice, scientists believe that intelligence can expand and fluctuate (12)_____ mental effort.

     Now, a new Web-based company has taken it a step (13)_____ and developed the first “brain training program” designed to actually help people improve and regain their mental (14)_____.

     The Web-based program (15)_____ you to systematically improve your memory and attention skills. The program keeps (16)_____ of your progress and provides detailed feedback (17)_____ your performance and improvement. Most importantly, it (18)_____ modifies and enhances the games you play to (19)_____ on the strengths you are developing—much like a(n) (20)_____ exercise routine requires you to increase resistance and vary your muscle use.

答案精析：固定搭配辨析题。根据语意“一家网络公司________采取行动，开发了第一个‘大脑训练项目’”。由前文可知，可以通过训练大脑来改善大脑的功能，之后以网络公司开发的项目为例来证实之前的观点，上下文是一种递进关系，即该公司采取了进一步的行动。故本空应填入further。

错项排除：A项back和C项aside无法表示更进一步的行动，与原文意思不符，故排除。D项around不和step一起搭配使用，故排除。