Shanghai people's square underground mark is studied as an example, data are collected through questionnaire survey and sorted out, and factor analysis method is then used.

以上海市人民广场地下商场为研究实例，通过问卷调查收集数据，并对所收集到的数据进行整理，然后进行因素分析。

youdao

Prior to construction, delineate and mark all property boundaries and underground utilities.

在建造之前，画出并标出所有的财产边界和地下设备。

youdao

Power cable route protection zone: the areas between two parallel lines formed by 0.75 meters on both sides of the ground mark of underground cable route;

电力电缆线路保护区：地下电缆为线路两侧各零点七五米所形成的两平行线内的区域；

youdao

The commission, from Art on the Underground, is part of celebrations to mark the Tube's 150th anniversary.

BBC: Mark Wallinger unveils labyrinth Tube art

Vintage Tube logos form the background of a commemorative Oyster card to mark the 150th anniversary of London Underground rail service in London.

BBC: Oyster card celebrates 150th Tube anniversary

Like other rescue workers whose job it is to venture underground, Angeli and Steelman spray orange paint to mark the places they have searched.

CNN: workers