Beginner Level Advanced Level
INTERMEDIATE LEVEL
Content
difficult(y) ☊ 
sự khó khăn ☊
→ → →
OXF3000N 
sự khó khăn nỗi khó khăn điều cản trở 
difficulty
like: sự khó khăn → →
rank sb/sth (+ adv./prep.): The tasks have been ranked in order of difficulty. ☊ rank ☊
If you wish really hard, maybe you'll get what you want. ☊ wish ☊