re-
/riː/prefix
1
- once more; afresh; anew表示“又”, “再”, “重新”, “反复”：
reaccustom
reactivate.
1.1
- with return to a previous state表示“返回原状态”：
restore
revert.
2
- （亦作red-）in return; mutually表示“回复”, “回报”, “相互”：
react
resemble.
2.1
- in opposition表示“反对”, “对立”：
repel
resistance.
3
- behind or after表示“在后”, “往后”：
relic
remain.
3.1
- in a withdrawn state表示“退隐”, “隐秘”：
recluse
reticent.
3.2
- back and away; down表示“（离）开”, “（放）掉”, “去”, “下”：
recede
relegation.
4
- with frequentative or intensive force表示“反复的”, “加强的”：
refine
resound.
5
- with negative force表示“否定的”：
recant.
USAGE
In modern English, the tendency is for words formed with prefixes such as re- to be unhyphenated: restore, remain, reacquaint. One general exception to this is when the word to which re- attaches begins with e： in this case a hyphen is often inserted for clarity: re-examine, re-enter, re-enact. A hyphen is sometimes also used where the word formed with the prefix would be identical to an already existing word: re-cover （meaning 'cover again', as in we decided to re-cover the dining-room chairs） not recover （meaning 'get better in health'）. Similar guidelines apply to other prefixes such as pre-.
词源
from Latin re-, red- 'again, back'.