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.（1）选？
动词搭配+从句辨析本句句义为“我们会突然想不起来放钥匙_____”。划线处及之后的“_____we put the key just a moment ago”作remember的宾语从句。根据put的用法“put something in some place”（把某物放在某处）可知，空格处缺少的是地点状语，在四个选项中只有where表示地点状语，因此正确答案是D。why和when分别引导原因状语从句和时间状语从句，可放到空格处，但是无法做put的地点状语，所以排除选项A和B。that放在动词remember之后引导宾语从句，此时的that没有任何实际意义可以省略，而且that并不能充当put的地点状语，所以排除选项C。
