O
・Old habits die hard.
・On one condition.
・Once and for all.
・One day at a time.
・One way or the other.
・Out of the question.
・Out with it.
・Over my dead body.
P
・Please wait to be seated.
・Point taken.
・Promises, promises.
・Pull yourself together!
R
S
・Safety first.
・Same as usual.
・Save it!
・Saved by the bell.
・Say no more.
・Say what?
・Says who?
・Separate checks, please.
・Shake it!
・Shame on you!
・Sleep tight.
・Snap out of it.
・So far, so good.
・So what?
・Something’s fishy.
・Something’s funny.
・Sorry it’s messy.
・Sounds awful!
・Sounds good.
・Sounds like a plan.
・Spare me.
・Speak for yourself.
・Speak of the devil.
・Speak up.
・Speaking of which, …
・Spill the beans.
・Stick with it.
・Stop breathing down my neck.
・Strike while the iron is hot.
・Suck it up.
・Sue me.
・Suit yourself.
・Sure thing.
・Surprise me.