正确: The highly toxic substance was handled carefully. (剧毒物质进行了仔细的处理。)
错误: The highly-toxic substance was handled carefully.
正确: The proposal was well documented. The professor said: "This really is a well-documented proposal."
错误: The proposal was well-documented.
正确: He has a 42-foot-long boat. His boat is 42 feet long.
错误: His boat is 42-feet-long.
正确: We re-applied the coating. (我们又涂了一层。)
正确: He is one-quarter Irish. (他有四分之一的爱尔兰血统。)
正确: Twenty-one people participated in the experiment. (二十一个人参加了实验。)
正确: The third- and fourth-grade teachers met with the parents. (三四年级的老师和家长见面了。)
正确: Both full- and part-time employees will get raises this year. (全职和兼职的员工今年都会加薪。)
正确: We don't see many 3-, 4-, and 5-year-old children around here. (这里三、四、五岁的小孩比较少见。)
正确: Follow standard pre- and post-operative procedures. (术前、术后的程序都按照标准进行。)
若在首字母是大写的词前面加前缀（eg: non-English）、或前缀本身需要大写（eg: I-information）时，需要使用连字符。另外，若使用类似self-, all-, and ex-这些前缀时，也需要使用连字符。此外，若前缀的尾字母若该词本身的首字母相同时，通常需要加上连字符（eg: anti-intellectual）（不过也有特例）。
正确: A-frame, I-formation, self-control, anti-intellectual, de-emphasize, non-English
特例: unnatural, coordinate, cooperate(对于这些词是否使用连字符，杂志或出版商会有相应的行规。)
Download Tip Here: 如何正确使用连字符 (B部分)
Uni-edit English Writing Tip: How to use hyphens correctly (Part B)
Level of difficulty: Advanced
Editors at Uni-edit often need to correct the use of hyphens during English editing of manuscripts. Correct use of hyphens shows the author's advanced command of English and helps to make detailed descriptions clear.
The hyphen, which is a very short horizontal line that looks like this '-', is very helpful to disambiguate modified words, which will make your writing clearer. Hyphens are used often in all academic writing in English.
Hyphens cause writers more trouble than any other form of punctuation, except perhaps commas. This may be because the hyphen has no analogue in speech; it is punctuation created purely by the needs of print. The point of the hyphen is to avoid ambiguity for the reader.
Let's look at some common uses and misuses:
Rule: Do not hyphenate when the adverb ends in 'ly'
Correct: The highly toxic substance was handled carefully.
Incorrect: The highly-toxic substance was handled carefully.
Rule: Do not hyphenate compounds that come after the noun
Don't hyphenate most compound modifiers if they occur after the noun being modified, even if hyphenating them before the noun.
Correct: The proposal was well documented. The professor said: "This really is a well-documented proposal."
Incorrect: The proposal was well-documented.
Correct: He has a 42-foot-long boat.
Correct: His boat is 42 feet long.
Incorrect: His boat is 42-feet-long.
Use a hyphen for repeated actions
Correct: We re-applied the coating.
This means the coating was applied for a second time. The hyphen makes it clear for the reader that the ‘re’ means a repeated action.
Writing some numbers
Use a hyphen for writing numbers twenty-one to ninety-nine and fractions.
Correct: He is one-quarter Irish.
Correct: Twenty-one people participated in the experiment.
With a series of nearly identical compounds, we sometimes delay the final term of compound until the last instance, allowing the hyphen to act as a kind of placeholder.
Correct: The third- and fourth-grade teachers met with the parents.
Correct: Both full- and part-time employees will get raises this year.
Correct: We don't see many 3-, 4-, and 5-year-old children around here.
Correct: Follow standard pre- and post-operative procedures.
Adding certain prefixes
When a prefix comes before a capitalized word or the prefix is capitalized, use a hyphen. The prefixes self-, all-, and ex- nearly always require a hyphen, and when the prefix ends with the same letter that begins the word, you will often use a hyphen, but not always.
Correct: A-frame, I-formation, self-control, anti-intellectual, de-emphasize, non-English
Special cases: unnatural, coordinate, cooperate (a journal or publisher may have house rules on whether or not to hyphenate these words)
END OF TIP