plugholes
n.
插孔，（压载水柜）放水孔，密封采空区的密封孔道( plughole的名词复数 );
例句:
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Plugholes Many people say that every plughole north of the Equator swirls the same way.
来自BBC
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"Splish Splash," his first hit, features gurgling plugholes, rock 'n' roll yelps and plenty of Miss Molly.
来自BBC