To answer the first part of your question, I'd like to say that our studies were very extensive.
你问题的第一部分,我要说的就是我们的研究非常广泛。
Byrd now knew that he would be able to reach the South Pole which was 300 miles away, for there were no more mountains in sight.
伯德这时知道他能够顺利飞抵300英里以外的南极了,因为前面再没有山了。