为什么前缀有多个意思（以及他们的意思）

1. counter-

meaning: opposition, opposite direction-相反的，相对的

example: counter-attack, counteract

2. extra-

meaning: outside, beyond-外面的，超越的

example: extracurricular, extramarital

3. hemi-

meaning: half-一半

example: hemisphere

4. inter-

meaning: between, among-在...之间

example: interact, interchange

5. non-

meaning: absence, negation-非，无

example: non-smoker, non-alcoholic

6. post-

meaning: after in time or order-之后（时间上和空间上）

example: postpone

7. re-

meaning: again-再次

example: repaint, reappraise, reawake