English Words Usage

INSTANT as "short period of time" (noun)

ADJ

brief, fleeting: For a brief instant, I thought she was going to fall

one, single: His news was too important to be contained for a single instant longer

VERB + INSTANT

pause for: He paused for an instant before continuing

PREP

for an ~: Just for an instant I thought he was going to refuse

in an ~: It was all over in an instant

~ after/before: She woke up in the instant before the phone rang

INSTANT as "single point in time" (noun)

ADJ

(any) given, (any) one: At any given instant the distribution of molecular speeds is always constant under the same conditions

very: He took out his keys to lock the door. At that very instant the door flew open and a man ran into the room

PREP

at … ~: The bomb could go off at any instant