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。

youdao

Research on expanding of urban social space;

城市社会空间扩展的研究；

youdao

And it's easy to upgrade by setting the expanding space aside.

预留可拓展空间，便于升级。

youdao

And it's easy to upgrade by setting the expanding space aside.

预留可拓展空间，便于升级。

youdao