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BBC事實查核（BBC Verify） 對這些說法進行了核實。，更多细节参见WPS下载最新地址
Optical-based smoke alarms use light instead. They are slightly better at detecting the large smoke particles created by slow, smouldering fires. When such particles enter a chamber in the device, they scatter light from a small light source, which is then picked up by a photoelectric sensor.，这一点在同城约会中也有详细论述
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London has the highest number of rough sleepers -1,277 - but the rate of rough sleeping rose steepest year-on-year in the north east of England, where numbers increased by 31% to 162.