Нужно вставить слова must или mustnt.   A real friend ____ ...

Motes

Нужно вставить слова must или mustnt.
 
A real friend ____ always help you if you need help.
A real friend_____ tell your secrets to anyone.
A real friend _____ make you happy if you are sad.
A real friend _____ listen to you if you have a problem.
A real friend _____ tell you lies.
A real friend _____ share his/her bicycle with you havent got one.
Заранее  спасибо!