I saw “upon” in a document where “on” would be correct.
Problem:
“Upon” and “on” are not synonyms.
Explanation:
The primary definition of the preposition “upon” is up and on — conceptually, a contraction of the adverb up and the preposition on. A typical final definition indicates that “upon” can be used in place of “on”; however, this substitution is only preferred for metrical or euphonic reasons.
Solution:
Use “upon” when you want to indicate up and on; use “on” otherwise.
I saw “utilize” in a document where “use” would be correct.
Problem:
The verbs “utilize” and “use” are not synonyms.
Explanation:
The verb “utilize” means to put to profitable use. For example, The drill sargeants could not use the PDAs would mean that the drill sargeants were unable to operate the PDAs, whereas The drill sargeants could not utilize the PDAs would mean that the drill sargeants could not find ways to deploy the PDAs in the boot camp.
Solution:
Use “utilize” when you want to indicate to put to profitable use; use “use” otherwise.
I saw the wrong one used recently.
Problem:
“In line” and “inline” are not synonyms.
Explanation:
“In line” tells where and is an adverb: “Bob is in line to receive a raise.”
“Inline” tells what and is an adjective: “Bob enjoys inline skating.”
Solution:
Use “in line” when you want to indicate where something or someone is.
Use “inline” when you want to describe what something or someone is.