求翻译：城是由城、堡发展而来。作为军事上的防御工程的城、堡，早在原始公社末期就开始了。由于它能起有效的防御作用，进入阶级社会以后，得到了普遍的发展。是什么意思？

City by city, Fort evolved. As a military defense project of the city, fort, as early as the late primitive began. As the role it can play effective defense, enter the class society, has been widespread development.

City development is by the city, Fort. As a military defense works in the city, Strasbourg, as early as late yuncong begins. Since it can play an effective role of defense into class society, that have received widespread development beyond.

The city is by the city, the fort development comes.In the achievement military defense project city, the fort, as early as started in the primitive commune last stage.Because it can play the effective defense role, enters after the class society, obtained the universal development.

City is a city, evolved. As a military fort on the defense works of the city, as early as in the original end of the commune began. Because it can play an effective role, after entering the class society, has been common for development.

City is a city, evolved. As a military fort on the defense works of the city, as early as in the original end of the commune began. Because it can play an effective role, after entering the class society, has been common for development.