long time,no see...پارسال دوست امسال اشنا
tit for tat...این در به اون در
I smell a rat....به چیزی شک کردن
don't be a wet blanket...don't spoil others pleasure
I have a bone with u...u annoy me
I'm on sea...I understand nothing
how on earth are u doing here?...surprised a lot by seeing someone somewhere!!
here a few idioms,they r informal I think...