Prepositional Idioms

Here we organize idioms with fixed meanings formed by “preposition + noun.” They are important for reading, English composition, and listening.

Basic Rules

Idioms beginning with at:
- at a loss“not knowing what to do” “I was at a loss what to do.”
- at any rate“in any case” “At any rate, we must try.”
- at first sight“at first sight” “She fell in love at first sight.”
- at random“randomly” “Choose a number at random.”
- at the mercy of“at the mercy of” “The ship was at the mercy of the storm.”
Idioms beginning with in:
- in vain“uselessly” “He tried in vain to open the door.”
- in advance“beforehand” “Pay in advance.”
- in person“directly / personally” “Meet me in person.”
- in short“in brief” “In short, you're fired.”
- in spite of“despite” = despite “In spite of the rain, we went out.”
Idioms beginning with on:
- on purpose“intentionally”← the opposite of “by accident（by chance）”
- on the contrary“on the contrary”
- on the whole“on the whole”
- on time“punctually”← distinguish it from “in time（before it is too late）”
Idioms beginning with out of:
- out of the blue“suddenly”
- out of order“not working” “The vending machine is out of order.”
- out of date“old-fashioned” / out of question“beyond question” / out of the question“impossible”（the meanings of the former and latter are opposite）
Others:
- by chance“by chance” / by mistake“accidentally” / by far“by far”
- for good“permanently” / for the time being“for now”
- of one's own“one's own” “a house of my own”

Points to Note

① Difference between on time and in time: on time = at the scheduled time（punctual）; in time = before it is too late（with time to spare）.
② out of question vs out of the question: the presence or absence of the definite article the reverses the meaning! The former means “beyond question,” and the latter means “impossible.”
③ at all vs at all costs: at all means “at all” in negative sentences; at all costs means “whatever the sacrifice.”
④ There are also idioms of three or more words, such as once and for all, meaning “finally and completely.” “Let's settle this once and for all.”

Practice

1. Translate “He arrives at school on time every day” using on time.
2. Choose the appropriate idiom: He failed (in vain / on purpose) to make us laugh.（He tried to make us laugh but failed.）
3. Translate “Suddenly, he said that he was going to move” using out of the blue.