Welcome, Tatung!
It's getting late to put in Gladiolus bulbs, unless you are gardening in one of the mildest parts of the UK. Most of the florist's kind will grow quite tall, about 5-7 ft., and the ones sold as "Landscape Gladiolus" usually run 2-4 ft tall, though they can get over enthusiastic. It should have said how tall they were supposed to grow on the box. Unfortunately, they probably will not keep in the box over the winter, without having had some growth this summer, so you may have to throw the unused bulbs away, now. For future reference, I would plant all the Gladiolus bulbs in spring and early summer, although you can make successive plantings a week or two apart to stretch out the bloom season.