托福考试

【单选题】
A、The new technology used to build roads
B、The ability to transport goods over land
C、The trade in grain and cotton
D、The linking of smaller local roads into one long road
网考网参考答案：C
网考网解析：
[听力原文] According to the prof, what cause the growth of the US economy about 200 years ago document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>