In fact,Christopher Columbus used a version of it when he set sail in search of the New World - which caused him some na
问题描述：
In fact,Christopher Columbus used a version of it when he set sail in search of the New World - which caused him some navigational problems,since Ptolemy had calculated wrongly the size of the Atlantic and was unaware that the Pacific Ocean existed.
字面上是 不知道大西洋存在 还是不知道存在着的大西洋
就是说 Pacific Ocean（主） existed （动词）.
还是说 Pacific Ocean（主） existed （形容词）.
答
Pacific Ocean（主） existed （动词）
因为that 后边是跟从句的
没有意识到大西洋的存在