the United States imported $4.1 billion worth of seafood and agricultural products from China in 2006.In 1995,it was $80
问题描述：
the United States imported $4.1 billion worth of seafood and agricultural products from China in 2006.In 1995,it was $800 million.
为什么要加个worth of ,帮我分析一下,从语法、翻译、并给我举几个例子说明一下这种用法,
就是$4.1 billion后面
答
是价值,全部货物的价值,不是全部用美金购买的进口,可以是别的币种来付款,或以以物易物来交换.如果少了worth,就变成直接以美元购买.