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“这个网络课程还可以________学习进度，并且给予详尽的信息反馈。”根据and后面的内容可知，and前后存在一种先后顺序的关系，要先对学习进度有所了解，之后才可给出反馈。keep track of表示“记录；跟踪”，故本空应填入track。

错项排除：A项hold“抓住；控制”和C项order“秩序”代入空格后意思与原文不符，逻辑不通顺，故排除。D项pace“步调”通常用keep pace with表示“与……并驾齐驱”，故排除。