A saturated uniform packing is difficult to obtain. 要獲得飽和均勻的裝填是困難的。
You have probably seen these in movies, where the soldiers load the cannon with gun powder and a cannon ball and light it. 你經(jīng)?？梢栽陔娪爸锌吹?，士兵門(mén)用火藥裝填加農炮，然后裝入炮彈，接著(zhù)點(diǎn)火。
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