Must, mustn´t, don´t need - British English
1. The use of must , must not (mustn't) and need not (needn't) The modals must , must not and need not have the same form regardless the subject. There is no ending with he/she/it. ► If you want to say the sth. is unnecessary, use need not , not must not. (The negation of must means not allowed to .) I must play football. = I have to play football. I need not play football. = I do not need to play football. = I do not have to play football. I must not play football. = I am not allowed to play football. You can use must only with Simple Present. If you want to use it with other tenses, you need the form have to . This form is not the same regardless the subject. Look at the following table. Modal Substitutes I must p...