Can be used in Zone 20 zone 21 and Zone 22 dangerous places. Can be used in explosive or flammable dust atmosphere.

粉尘防爆照明应急两用灯，21区，22区危险场所。 含有爆炸性或可燃性粉尘环境。

youdao

Where, following an abnormal condition, the removal of dust accumulations or layers cannot be assured, then the area is to be classified zone 21.

如果不能保证排除可燃性粉尘堆积或粉尘层时，则应划分为21区。

youdao

Spurs have taken 33 points from 21 matches since Harry Redknapp took charge, a run which has seen them pull away from the relegation zone after their poor start to the campaign.

自从雷德克纳普接手球队，热刺已经在21场比赛中拿到了33分，看起来他们已经从赛季初的糟糕开局中摆脱并逃离了降级区。

youdao

Alan Pardew's side have collected just seven points from their last ten games and now sit two places above the relegation zone on 21 points.

CNN: Silva brace keeps Man City in title hunt

Phillips also announced that this year's tournament, which runs from June 21 to July 4, will be a "World Cup-free zone", with football fans denied the chance to watch matches on the big screens at the All England Club.

CNN: Wimbledon champions to receive ?1 million prize money

They say there is particular concern over the very long-lived northern low pressure zone of circumpolar winds, called a vortex, found at between 13 and 34 km (8 and 21 miles) above the Earth's surface.

BBC: By Environment Correspondent Alex Kirby