idiom: hold the fort

0Hi my EnglishForward friends,02br
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00I'm currently making a subtitles to my favourite movie in order to improve my english02br
00and I came across there to very interresting idiom:"hold the fort". It means take someones02br
00duty or responsibility in his absence...02br
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00That particular person said02br
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01i01b00Hold down the fort for an hour.02br
00I've just got to take care of some stuff.02b02i02br
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00Anyway, please what is the difference between just 01i01b00hold the fort02b02i00 and 01b01i00hold down the fort02i02b00?? I don't feel 02br
00the difference between these two phrases, but maybe there is something...I don't know.02br
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00thank you in advance.02br
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00With regards02br
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00JCD0-