填词补文：下面的短文有10处空白,短文后列出12个词,其中10个取自短文,请根据短文内容将其分别放回原有位置,以恢复文章原貌。

People of early civilizations built roads of a sort. However, the first good road  were the Romans. They built the earliest network of hard-surfaced roads. The Romans their road building about 300 B. C and continued for about five hundred years.
Roman roads were good because the people  how to lay a solid, thick base. On top of this, they put a pavement（路面）of flat Their roads were a bit  in the center than on the sides. Along the sides ran ditches（沟渠）so that the  could run off. These roads were also very They went over most of the hills instead of around them.

The Roman roads were used by soldiers. At first, these roads went through Italy. Then, as the Roman Empire spread, roads were built in other of Europe. In all they laid about 50.000 of roads.