新概念英语2册43课第一句话.In 1929,three years after his flight over the North Pole,the American explorer,R.E.Byrd,successfully flew over the South Pole for the first time.我有俩个问题：1.successfully flew over the South Pole for the first time的意思是他第一次穿越南极,并且穿越成功了.还是说他穿越了好几次,这是第一次成功.无论这是哪一种意思,请帮我写出另一种意思做对比.2.three years after his flight over the North Pole,这里的after为什么要放中间,读起来怪怪的,到底是说three years after 还是说after his flight over the North Pole,请帮我分析下这小部分句子.

新概念英语2册43课第一句话.
In 1929,three years after his flight over the North Pole,the American explorer,
R.E.Byrd,successfully flew over the South Pole for the first time.
我有俩个问题：
1.successfully flew over the South Pole for the first time的意思是他第一次穿越南极,并且穿越成功了.还是说他穿越了好几次,这是第一次成功.无论这是哪一种意思,请帮我写出另一种意思做对比.
2.three years after his flight over the North Pole,这里的after为什么要放中间,读起来怪怪的,到底是说three years after 还是说after his flight over the North Pole,请帮我分析下这小部分句子.