A-A+
A．The new technology used to build roadsB．The
问题详情
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
参考答案
正确答案：C
解析：According to the professor, what cause the growth of the US economy about 200 years ago?
