[解析]
(1)D.主旨大意题。根据文章"Lost Underground is a story about four school children who went on a trip to some caves." 可知,Lost Underground 是一个关于四个学生去洞穴旅行的故事。所以Lost Underground是一部关于孩子们去了一些洞穴旅行的故事。故选D。
(2)B.细节理解题。根据文章"They thought it would be fun to explore the cave alone.""他们认为独自探索洞穴会很有趣。"故选B。
(3)D.细节理解题。根据文章"The deeper they went,the more lost they became.They were frightened.They started shouting for help...""他们走得越深,就越迷路。他们很害怕。他们开始大声呼救……。"可知,当四个孩子深入洞穴时,他们感到害怕,大声呼救。故选D。
(4)C.推理判断题。根据They climbed out of the river onto the riverbank.They saw the bus with the other children in the distance.他们从河里爬到河岸,他们看到了远处载有其他孩子的公共汽车,可推测并不是向导找到了他们,而是他们自己找到了队伍。故选C。
(5)B.细节理解题。根据They climbed out of the river onto the riverbank.They saw the bus with the other children in the distance.孩子们得以离开洞穴他们从河里爬到河岸上。他们看到公共汽车和远处的其他孩子。可推测故事的结尾是迷路的孩子们从河里爬到河岸上,他们得救了。故选B。