MUST / MUSTN´T

• We  used must and mustn´t + the infinitive  to talk about rules or obligation.
• we often use must / mustn´t + with you In this situation , you means people in general.

AFFIRMATIVE SENTENCES       NEGATIVE SENTENCES

-You must have  a valid ticket       -You mustn´t eat on the rain

          -You must stand up behind the line   - You mustn´t carig bikes on trains