Download speeds drop-off by an average 30 per cent, mainly because of physical barriers and interference from microwaves, baby monitors and other radio devices., 其中，wi-fi的平均下载速度要慢上三成，主要是由于物理障碍，以及来自微波炉 ...

Still, when cities go dark, WhatsApp, Signal, and previously, Skype, have served as technological life rafts that keep aid ...