must not和mustn't沒有什麽區別，就是壹個縮寫和壹個不縮寫的區別。must not中文釋義：不能;不準;壹定不能。例句：We must not be soft on enemies.我們對敵人絕不能手軟。
mustn't例句
Keep down! You mustn't let anyone see you.
蹲下！壹定不要讓人看見妳。
You mustn't leave the gate open.
妳壹定不要讓大門敞開著。
You mustn't say things like that.
妳千萬別說那樣的話。
I mustn't be late or Dad will go up the wall.
我不能晚了，否則爸爸會發脾氣的。
We mustn't let these minor details obscure the main issue.
我們不能讓枝節問題掩蓋主要問題。