An idiom is an expression, which consists of at least two words that naturally seem to go together. It is something that native speakers of a language can usually quickly recognize, but is often challenging for those learning English as a secondary language, or for those who grew up speaking an English dialect that frequently breaks conventional idiom rules.
If you see one of these in a sentence, make sure the other half is present.
Not only … but also
Incorrect: Not only did we see the Eiffel Tower, but we saw the Louvre.
Correct: Not only did we see the Eiffel Tower, but also we saw the Louvre.
Between … and
Incorrect: Between cookies or crackers, I like cookies best.
Correct: Between cookies and crackers, I like cookies best.
As … as
Incorrect: Her hair was as pretty than my sister’s.
Correct: Her hair was as pretty as my sister’s.
Either … or / Neither … nor
Incorrect: Neither my best friend or I wanted to go shopping.
Correct: Neither my best friend nor I wanted to go shopping.
The second way that the ACT will test idioms is when they involve prepositions. A preposition is a word that typically describes location. Many phrases in English are only constructed correctly when used with certain prepositions.
Incorrect: Her experience was limited with secretarial work.
Correct: Her experience was limited to secretarial work.
Incorrect: I am so proud for my brother!
Correct: I am so proud of my brother!
Incorrect: When I was little, I was afraid from monsters.
Correct: When I was little, I was afraid of monsters.