18,-27,36,( ),54 ["44","45","-45","-44"]
7/9,13/9,20/9,28/9,( ) ["25\/9","37\/9","26\/9","8\/3"]
0,6,24,60,120,( ) ["180","210","220","240"]
成人主要的造血器官是:() ["肝","脾","淋巴结","卵黄囊","骨髓"]
《山东省新旧动能转换重大工程实施规划》中提到现山东省新经济规模偏小,新兴产业占比低,在人工智能、工业互联网、车联网等领域实力整体偏弱,新业态、新模式处于起步或跟跑阶段,()对经济发展的引领支撑作用尚未充分发挥。 ["新业态","新动能","新模式","新发展"]
简述自然资源的性质。