VOA慢速英语:NASA Working Toward Mission to Mars

短语讲解：

1. They are a new Space Launch System, Orion spacecraft, a deep space environment for astronauts to live in, and new methods for entry, descent and landing.

live in 居住
例句：We used to live in Shanghai but now we live in Beijing.
我们以前住在上海，但现在住在北京。

2. The agency is asking for ideas from the public on how to get people to Mars and how they can stay.

ask for 要求
例句：He had the audacity to ask for an increase in salary.
他竟然厚着脸皮要求增加薪水。

3. It is already known that at one point in time Mars had conditions that could have supported life.
 
at one point 一度;在某一刻
例句：At one point china had over 800 of them.
中国的啤酒厂曾一度突破800家。