The technologically compromised space shuttle program has just come to an end, with no successor.
出自-2013年12月阅读原文
The rising volume of trade – more goods and services shuttling in and out of the United States – is good news for many sectors.
出自-2011年12月阅读原文
This year's shuttle mission is a big step in space exploration.
出自-2011年12月听力原文