[英語慣用語]
Hold your horses. = Hold on./Slow down.
字面意思是勒住馬韁，引伸意思是，耐心點。
This idiom is very common and is used when you want to tell someone who's rushing to stop or calm down. It was most likely first used around the mid 1800s, when soldiers were told to "hold their horses" and wait for orders.
E.g.
A: I didn't study, but I am still going to take the TOEFL test tomorrow!
B: Hold your horses! You don't want to waste all that money. Study before you take it!
Sources:
http://en.wikipedia.org/wiki/Hold_your_horses
www.bbc.co.uk/.../120427_hold_your_horses.shtml
http://usacac.army.mil/CAC2/csi/CSIBattlemaps.asp
(In the painting, the general is telling his men to hold their horses and wait for the next order.)
