11.2 Discussing Safety Produceres.
by Wendy Aguilar

1. Grammar
1.1. Must
1.1.1. All pilots must have license.
1.1.2. (= They have to have one.)
1.1.3. You mustn't carry dangerous items on planes.(= You´re not allowed to.)
1.1.1. All pilots must have license.
1.1.2. (= They have to have one.)
1.1.3. You mustn't carry dangerous items on planes.(= You´re not allowed to.)