■ long

1) 作为副词，肯定時放在句末不能單用，例如不能说 *He stayed long. 但可以说 He stayed a long time (for a long time). 或者否定或疑问时说 He didn't stay long. 或者 Did he stay long? 或者前后加上别的单词如 He stayed too long. 变了形的 long 也可以。

• He stayed longer.他停留时间更长些。
• We can't say：“We're the biggest and we've been at it the longest, so de facto we win.”我们不能说：“我们这一家规模最大，而且干这一行的时间最长，我们就自然而然会取胜。”

同某些动词连用而且放在动词组之中，也可以。

• I've long admired your style of writing.我久仰您的文笔。
• I have long thought of retiring at the age of 55.我很久以来一直打算五十五岁就退休。
• Those laid-back days are long gone. (US News & World Report, Oct. 2, 2006)那些悠闲的日子早已过去。

用以修饰另一个时间状语时也可以单用。

• We used to live in Paris, but that was long before you were born.我们从前常住在巴黎，不过那是你还没有出生之前很久的事了。
• Long after the accident he used to dream that he was dying.直到事故过了之后很久，他还常常做梦，以为自己要死了。
• They kept talking long into the night.他们一直谈到深夜。

放在句首作为副词也可以单用。

• Long the domain of amateur painters, watercolors had gained professional respectability in 1866 with the formation of the American Water Color Society.水彩画本来很久以来一直是业余画家的领域，但随着 1866 年成立了美国水彩画协会，水彩画获得了受人尊重的专业地位。
• Long the target of people who blame soda's calories and popularity among young people for contributing to rising childhood obesity, the nation's largest beverage distributors say they will stop selling non-diet sodas to schools and start serving reduced sizes of other drinks. (The Associated Press, May 4, 2006)那些全国最大的饮料批发商们，长期以来一直被指责，说苏打水热量高，又受年轻人欢迎，造成儿童肥胖症增多，现在他们说，他们将停止向学校出售非节食型苏打饮料，而开始提供小型的其他饮料。

2) long 作为形容词，有时候会越出对单个名词本身的长度说明，变成对复数名词的数量说明。

• Nurses have to work long hours.本来一小时多长就是多长，丝毫不能增减，这里的 long 不是指每个 hour 的长度，而是指多个 hours 加起来的长度，也就相当于 many hours：“护士们要干多个钟点的活。”
• We were married for ten long years.我们结婚一起有十年之久。

不但在时间上如此，在空间上 long 也有类似的用法。

• There is in the Midlands a single-line tramway system which boldly leaves the county town and plunges off into the black, industrial countryside, up hill and down dale, through the long, ugly villages of workmen's houses... (D. H. Lawrence, England, My England, Chapter II)密德兰有一条单线的电车，它勇猛地开出郡首府，一下子冲进乌黑的乡村工业区，爬高爬低，穿过长串长串的丑陋工人住宅村…

3) for a long time 与 for long 都是表示某一延续行动或状态延续很久（for long 通常用于否定句），但是在否定句中起不同的作用，前者“管”否定，后者被否定所“管”。

• She didn't speak for long.她没有讲多久。
• She didn't speak for a long time.她很长时间不说话。
• He didn't live there for long.他在那边没住多久。
• He didn't live there for a long time.他很久都没有住在那边。

这是比较容易辨别的，因为状语不同。但是有时候状语没有区别，就可能产生歧义。例如：

• You mustn't sleep till tomorrow morning.

如果是 till tomorrow morning 管 not，意思就是“没到明天早上你可不能睡下来”(sleep 代替 begin to sleep 或 go to bed)；如果是 not 管 till tomorrow morning，意思就是“你可不能睡到明天早上才起床”。两者在语调上有区别，但是书面上看不出来，要靠前后文和语境来判别。