i've never bought trousers from Zara, but Karen Millen trousers are the same.
I tried on some lovely trousers in there, but they were stupidly long - you would have had to be over 6ft tall for them to fit properly!
The shop assistant said to me "Well I think they make them so long because it is easy to take them up, but you can't alter them if they're too short"
I didn't buy them because I wasn't paying out another £10 to get them taken up properly!