Aider moi svp , c'est un dm et je comprend rien

a) This red sweetshirt is cheapest than the green one, and it looks best too.
b) In the late '70s, people started buying more flashy clothes. It was best Saturday Night Fever.
c) John loves Australia. He thinks it's more beautiful country in the world. He visited Scotland last year. He founds it more interesting.

Voila, en esperant t'avoir aidé! ^^