[解析]
(1)D.主旨大意题.通读全文,本文主要讲述了一个人造设备使得人们和他们的宠物能够聊天,借此可以安抚不喜欢离开主人的宠物,因此最佳标题为一个孩子发明的可以安抚狗狗紧张情绪的装置;故选D.
(2)A.细节理解题.根据文章第二段she invented a device that allowed pet owners to video chat with their pets,可知这个装置安抚狗情绪的方式是允许狗和主人视频聊天,故选A.
(3)C.细节理解题.根据文章第三段"These finalists,selected based on their short video presentations,are working with mentors over the summer before heading to the final competition in St.Paul,Minn"可知,这些发明都具有一定的指导意义,就如同说明书一样,故选C.
(4)B.推理判断题.根据文章最后一段"Their projects include a fuel cell that transforms cut grass into electricity and an app that rewards drivers for not texting or calling"可知,这个设备的发明可以解决了人们每天办不到的问题,他们都是日常问题的可能的解决方案,故选B.