Wi-fi hot spots are large — about the size of a football field — but those signals had to pass through a lot of masonry before they got to my laptop.

虽然Wi - fi热点的覆盖面有足球场那么大，但信号在到达我的电脑之前还要穿过层层水泥。

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In less than five short years the number of U.S. households with a Wi-Fi network has gone from zero to 4.3 million, and you can barely pass a street corner in any big U.S. city without seeing a public Wi-Fi hot spot.

FORBES: Wi-Fi Today