must 表示“偏偏”在词典上可以查到的,你说没有查到,可能是你查的词典是学生词典。我查了一下,柯林斯词典就有相关的用法说明。
must 表示“偏偏”指某事发生得不早不迟,就在某个当紧的时候,多指某些不受欢迎的事情的发生(暗示生气或不耐烦)。又如:
Just when I was busy, the neighbor must come and chatter. 正当我忙碌的时候,邻居偏偏过来聊天。
John must choose the day I had company coming, to start painting the bathroom. 约翰偏偏选择我有客人来这天油漆浴室。
As I was sitting down to lunch. the electric bell must ring. 我刚要坐下来吃午饭,电铃偏偏这时响了起来。
有时表示主观上的偏执或固执,常可译为“偏”“偏要”。如:
Why must she be so nasty to me? 为什么她偏对我这样恶劣?
After I gave her my advice,she must go and do the opposite. 在我给她出主意之后她偏要反着干。
有时可译为“非要”“非得”“硬是”“硬要”等。如:
Must you make so much noise? 你就非得弄出这么大的声音吗?
Why must you always interrupt me? 你为什么硬是老要打断我?