Question

they are advised to travel by train(sd had better nha)

->

Answer 1

they are advised to travel by train(sd had better nha)

-> THEY HAD BETTER TRAVEL BY TRAIN.

STRUCTURE: HAD BETTER DO ST

Answer 2

they are advised to travel by train(sd had better nha)

->They had better travel by train

Form: HAD BETTER( Nên )+ V(inF)

Answer 3

=>They had better travel by train.