Hi Yan -- Ken is absolutely right, you need to grow the hardneck types to reliably get scapes. There are a LOT of different varieties... I grow "Music," which sends up some pretty impressive scapes and has bulbs with just 4-6 really large cloves. Are you planning to buy from a local source, or online? The online sites generally specify whether a variety is hardneck or softneck; from my experience, employees at local garden centers may or may not know the difference!
