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20th day of the month
20 days
締め切りは今月の二十日だ。
The deadline is the 20th of this month.
二十日までに届かなかったら連絡してね。
If it doesn't arrive by the 20th, let me know.
来月の二十日にまた病院に来てください。
Please come to the hospital again on the 20th of next month.