America is lagging behind in the STEM disciplines.
出自-2010年12月阅读原文
柯林斯高阶英汉双解学习词典释义
N-UNCOUNT
（覆盖水管、水箱或屋顶内部的）绝热材料，保温材料
Lagging is special material which is used to cover pipes, water tanks, or the inside of a roof so that heat does not escape from them or so they do not freeze.
英英词典释义
Noun
1. used to wrap around pipes or boilers or laid in attics to prevent loss of heat