Why It's Unique: With a 76-foot diameter, Yerba BuenaIsland Tunnel is the world's widest single-bore tunnel, an impressivefeat considering it opened in November of 1936.

独特之处： 直径达76英尺的耶尔瓦布埃纳岛隧道是世界上最宽的单孔隧道，1936年11月，这项令人印象深刻的工程落成开通。

youdao

The Bore is the diameter of the cylinder. The stroke is the distance the piston travels from BDC (Bottom dead center) to TDC (top dead center). The Bore is always mentioned first.

内径指的是气缸的直径；行程是活塞从下止点运行到上止点的距离。表述时，内径总是写在前面。

youdao

Mean bore diameter: arithmetical mean of the largest and smallest single bore diameters in one plane.

平均内径：同一平面上最大和最小内径的算术平均值。

youdao

The drill would use one of the three bore holes already made as a pilot and widen the diameter to about 28 inches, which officials have said is wide enough for the miners to be hoisted through.

CNN: New video shows trapped Chilean miners in good spirits