下列对横骨架式结构特点描述不正确的是:() ["建造方便","货舱容积损失少","船舶纵向强度大","常用于沿海中小型船舶"]
纵骨架式船体结构的优点是:() ①、纵向强度大; ②、船体重量轻; ③、适用于大型油船; ④、舱容利用率高 ["①、②、③","②、③、④","①、③、④","①、②"]
对于纵骨架式船体结构,下列说法不正确的是:() ①、纵向构件尺寸大; ②、增加了船舶的自重; ③、能充分利用舱容 ["①、②","②、③","①、③","①、②、③"]
当利玛窦等传教士进入中国时,正值()朝末期。
明清之际实学思潮的先导人物是() ["A.徐光启","B.黄宗羲","C.李之藻","D.顾宪成"]
()年间,正式实行闭关锁国政策。