Road Building

People of early civilizations built roads of a sort. However, the first good road _____（1） were the Romans. They built the earliest network of hard-surfaced roads. The Romans _____（2） their road building about 300 B.C. and continued for about five hundred years.
Roman roads were good because the people _____（3） how to lay a solid, thick base. On top of this, they put a pavement （路面）of flat _____（4） . Their roads were a bit _____（5） in the center than on the sides. Along the sides ran ditches （沟渠）so that the _____（6） could run off. These roads were also very _____（7）. They went over most of the hills instead of around them.
The Roman roads were used _____（8） by soldiers. At first, these roads went through Italy. Then, as the Roman Empire spread, roads were built in other _____（9） of Europe. In all they laid about 50,000_____（10）of roads.

A. builders
B. miles
C. stones
D. higher
E. correctly
F. straight
G. mainly
H. countries
I. clearer
J. began
K. water
L. knew