how you can chek if the timing belt it been change it

Look in the service history or see if theres a sticker near the belt. If theres no evidence and it is near the mileage to change it, get it changed anyway. It will be a lot less trouble than a damaged engine.

you can check the service records of the car if you have them or pull the cover and inspect the belt which is the best thing to do anyway,look for signs of cracking or splitting,or dry rot,if you see any of these replace the belt,usually you can look at a belt and sort of tell if its old or new,good luck on it.

service history

There is usually a little sticker placed on the top of the cover, which gives the date and mileage when it was changed if done at a shop or at the dealer.

If in doubt,replace it to be safe than sorry.It is not possible to tell,if the belt has been changed for a while,say 10,000 miles ago.