我们将可以删除的介词用红色标出
The mice’s blood pressure was elevated. [6 words]
The elephant teetered along the cliff’s edge. [7 words]
This project examined how increased global temperatures affect local fish hatcheries. [11 words]
以上的范文只要用两个字去替换删掉的介系词片语就可以成功缩短字数了。假设文章中充满上方这一类的句型，那删的字数可多了。
可以删掉介词的情况有很多，上方范文只是一小部分，而这一篇文章提到的也是其中之一。记忆力好的人应该还可以想起来使用动词名词形容易让人写出被动语态。
下方介绍那些状况的介系词片语你可以修改，同时介绍该怎么修改。
1，改成所有格:
许多高度相关的情况下，例如两个名词之间的所有权，就可以删掉中间的介词。例如，句子中有「Noun1 of Noun 2」或「Location1 in Location2」，直接将第二个名词往前移并加上「’」 变成Noun1’s Noun2。
The approval of the Food and Drug Administration was received yesterday. → The Food and Drug Administration’s approval was received yesterday.
The studies were conducted at Max Laboratories in Chicago. → The studies were conducted at Chicago’s Max Laboratories.
2，改成主动语态:
当被动语态的句子后面跟着「by」的时候 (Noun1 was/were + past participle + by + Noun2)，把by后面的名词改成句子主词写成主动语态。
The approval of the plan was given by the committee. → The committee approved the plan yesterday.
3，替换副词形式:
某些介系词片语可以改的更为坚定，例如:由「with」开头的片语。
The seller agreed with reluctance. → The seller reluctantly agreed.
He spoke with hesitation when he accepted the deal. → He spoke hesitantly as he accepted the deal.
By chance,
