trở thành một đề tài lớn 
to become a large topic [ trở ] : to return; to hamper, hinder; to turn, change
[ thành ] : (1) citadel, fortress, wall; (2) to, into; (3) to succeed; (4) to become; (5) honest, sincere
[ một ] : one; a, an
[ đề ] : (1) to write; (2) to propose; (3) to lift
[ tài ] : skill, talent, gift; skilful, talented
[ lớn ] : big, elder, large, loud
Most Common Compounds Set 1:
Most Common Compounds Set 2 :