1. achieve v. 取得;获得
achievement n. 成就
Cf. achieve high grades (goals) earn one’s respect (living, money) acquire skills/knowledge gain experience/support/reputation
2. average n. /adj.
平均;平均的
3. challenging adj. 有挑战性的
Cf. challenge n. 挑战;v. 挑战
meet the challenge; challenge sb. to do sth.
On average, below average, above average