Some bikes with slanting top tubes are measured as if there were a level top tube, they use the length that the seat tube would be if it was as high as the head tube.

而有些上管倾斜的车架， 会被当作水平上管的车架来测量。 立管长度就会从中轴中心量到立管上与头管一样高的位置。

youdao

You have a tube, a transparent--a tube--a hollow tube, and at the top of the tube you throw a ball through so it whips through the tube and it comes out.

用一根管子,一根透明中空的管子,从管子最上面,你丢进去一个小球,小球迅速穿过管子,飞出来

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In subsequent versions, the top tube has stayed, but much else has changed.

WSJ: Sjoerd Smit of Vanmoof: A Designer Spin on the Grandma Bike

The top tube also has lights built right into it.

WSJ: Sjoerd Smit of Vanmoof: A Designer Spin on the Grandma Bike

On top of the mess, one straight tube juts out, a square of gray duct tape hanging from it, flapping in the breeze, a flag of surrender.

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