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to drink up; to drink to the last drop; to drink (a glass) dry; to drain (one's glass); to empty; to down (a drink)
ビールを一気に飲み干した。
I drank the beer in one gulp.
彼は水を勢いよく飲み干している。
He is drinking up the water vigorously.
薬のために苦い漢方を飲み干す覚悟だ。
I am prepared to drink up the bitter herbal medicine.