为什么要用“mustn't”牛津英语第三册第一课的reading里有这么有句话：You really mustn't worry.这里为什么用mustn't?mustn't?的意思不是禁止吗?

为什么要用“mustn't”牛津英语第三册第一课的reading里有这么有句话：You really mustn't worry.这里为什么用mustn't?mustn't?的意思不是禁止吗? do you mustn't go across the road when the light is red?怎么翻译?为什么要用mustn't? 用don`t和mustn`t写英语作文 Can't 、mustn't 、shouldn't 的区别?（急）比如一句句子：He ______ be in the room,I didn't see him.莪知道要用can't,但是为什么呢?为什么不用mustn't 、shouldn't （英语）用mustn't造一个句子 英语情态动词区别There's no light on-they______be at home.为什么用can't 而不是 mustn't?You ___ play computer games before you finish your homework.是用mustn't 还是shouldn't?请说一下can't,mustn't 和shouldn't的区别,最好再 能帮我解决以下英语问题you talk so loud in the library.B mustn't C can't为什么答案是C.不是在图书馆用禁止的吗?mustn't应该是禁止吧 英国文化习俗!急用!要用英语写的!最好用上 must mustn't can can't! Can I swim in the ricer?No you mustn't.为什么答句回答用mustn't There's no light on.they____be at home.A:can't B:mustn't C:needn't D:shouldn't为什么用can't,而不用mustn't.mustn't不是表推测吗? 英语 you must have read this book, didn't you 为什么用didn'tyou must have read this book, didn't you 为什么用didn't,而不是mustn't you? haven't you? don't you?有mustn't you的说法吗? we_____play football on the street,It's too dangerous为什么用mustn't不用can't To make our city more beautiful,rubbish mustn't be thrown into the river.为什么用的是mustn't be thrown,而不能用can't throw? There's no light on.they____be at home.为什么用can't,而不用mustn't.mustn't不是表推测吗? 有关mustn't和can'tHe ______ be at home,because the light is off.用can't还是mustn't?为什么? 英语求教it's the reading-room!So you__eat lunch here.mustn't和 can't填哪个,为什么呢 关于英语选择提--Is Pro.Smith giving the speech today --It____be him .He is abroad right now.A mustn't B needn't C won't D can't 请问选哪个 并为什么要选它呢? 英语must和needmust引导的一般疑问句用 needn't作否定回答,为什么不用mustn't?带有must't的陈述句又与疑问句回答中的needn't有什么区别哪?