nghiền ngẫm một vấn đề 
to ponder a question [ nghiền ] : to crush, pound, grind
[ ngẫm ] : to ponder, reflect upon, think over, consider
[ một ] : one; a, an
[ vấn ] : to ask, question
[ đề ] : (1) to write; (2) to propose; (3) to lift
Most Common Compounds Set 1:
Most Common Compounds Set 2 :