And it's easy to upgrade by setting the expanding space aside.
预留可拓展空间，便于升级。
As the space for human activities expanding, study about underwater vehicle has become a hotspot.
随着人类活动空间不断扩大，水下机器人已成为各国研究的热点。
Research on expanding of urban social space;
城市社会空间扩展的研究；
Research on expanding of urban social space;
城市社会空间扩展的研究；
应用推荐